Ethernet Cable Not Working

If your Ethernet cable is not working, not detected, or connected without internet access, the issue may be caused by the cable, Ethernet port, router, switch, network adapter, wall jack, or device settings. The fastest way to fix the problem is to start with simple physical checks before moving into more advanced troubleshooting.

Begin by confirming both ends of the cable are fully connected, checking for link lights, restarting the connected devices, trying another Ethernet port, and testing a known working cable. If the problem continues, inspect the cable terminations, network adapter, device settings, and cable run for damage.

This guide covers the most common reasons an Ethernet cable stops working and explains how to determine whether the problem is with the cable, the connected equipment, or the network configuration.

Why Is My Ethernet Cable Not Working?

An Ethernet cable may not work because it is loose, damaged, incorrectly terminated, connected to a faulty port, or incompatible with the connected equipment. The issue may also come from a disabled network adapter, outdated driver, router problem, incorrect network settings, excessive cable length, damaged wall jack, or poor cable installation.

The most effective troubleshooting method is to isolate one part of the network at a time. A typical wired connection may include a computer or gaming console, a patch cable, a wall plate or keystone jack, permanent Ethernet cable, a patch panel, another patch cable, and a router or switch. Any one of these components can cause the connection to fail.

Before changing settings, identify the equipment being used and the exact symptom:

• Is the Ethernet cable not detected at all?
• Does the device show Ethernet connected but no internet?
• Is the connection dropping in and out?
• Is the cable working at a slower speed than expected?
• Did the problem begin after terminating or installing a new cable?
• Does the same cable work with another device?

Knowing the symptom helps determine whether to focus on the physical cable, connected equipment, or network configuration.

1. Check the Ethernet Link Lights

Most Ethernet ports have one or two small LED lights near the connection. These are commonly called link lights or activity lights. They can provide an immediate clue about whether the devices have established a physical Ethernet connection.

After plugging in the cable, look at the Ethernet port on the router, switch, computer, network adapter, or gaming console.

• No light: The cable may be loose, damaged, incorrectly terminated, or connected to a disabled or faulty port.
• Solid light: A physical link has likely been established.
• Blinking light: The port is usually sending or receiving network traffic.
• Different light color: Some equipment uses color to indicate the negotiated link speed.

A link light does not guarantee internet access or full network speed, but it confirms that the connected devices can detect one another at the physical layer.

If neither end shows a link light, test another cable and another Ethernet port before changing software settings.

2. Reconnect Both Ends of the Cable

A partially inserted RJ45 plug is one of the simplest and most common causes of an Ethernet connection problem. Disconnect the cable from both devices and reconnect it until the plug clicks into place.

Confirm that the locking tab is not broken and that the cable does not slide out of the port. A damaged retention tab can allow the connector to loosen even when it appears to be connected.

Check both ends, including any connection at a router, switch, computer, gaming console, wall plate, patch panel, or network adapter.

3. Restart the Connected Devices

Restarting the connected devices can clear temporary software, network, or negotiation problems. Turn off or restart the computer, gaming console, router, modem, switch, or network adapter involved in the connection.

If restarting the full network, begin with the modem or internet gateway, then restart the router and switch, and finally restart the connected device. Allow each device to fully power on before testing the connection again.

This can resolve temporary issues involving DHCP, IP address assignment, network adapter state, and speed negotiation.

4. Try a Different Ethernet Port

The Ethernet cable may be working correctly while the connected port is damaged, disabled, or improperly configured. Move the cable to another LAN port on the router or switch.

If the connection works immediately on another port, the original port may be faulty or disabled. If no ports work, the issue may be the cable, router, switch, device settings, or network service.

For more information about how these connections work, read our guide explaining what an Ethernet port is.

5. Try a Different Ethernet Cable

Testing a known working Ethernet cable is one of the fastest ways to isolate the problem. Connect the replacement cable between the same two devices and use the same ports.

If the replacement cable works, the original cable is likely damaged, incorrectly terminated, or incompatible with one of the connectors. If neither cable works, test the original cable with another device or Ethernet port.

Using a known working cable helps determine whether the fault follows the cable or remains with the equipment.

6. Temporarily Turn Off WiFi

Most computers automatically prioritize a working wired Ethernet connection over WiFi. However, temporarily turning off WiFi can make troubleshooting easier because it confirms whether the device is actually using the Ethernet connection.

After disabling WiFi, check whether the device still shows network or internet access. If the connection disappears, the computer may have been using WiFi rather than Ethernet.

If Ethernet still does not work, continue checking the wired network adapter and cable connection.

7. Confirm the Ethernet Adapter Is Enabled

A computer may have a working cable and port but still fail to connect if the Ethernet adapter is disabled. Open the device's network settings and confirm the wired network adapter is enabled.

The adapter may appear under names such as Ethernet, Local Area Connection, LAN, USB Ethernet, or the name of the network interface manufacturer.

Possible adapter status messages include:

• Connected: The physical connection is active.
• Network cable unplugged: The device does not detect a physical link.
• Unidentified network: A physical link exists, but the device has not established normal network access.
• Disabled: The adapter must be enabled before it can connect.

If the adapter is missing entirely, check Device Manager or the system information utility to confirm the network adapter is installed and recognized.

8. Run the Built In Network Troubleshooter

Modern operating systems include diagnostic tools that can identify common network configuration problems. Use the built in network troubleshooter or network diagnostics feature to check the Ethernet adapter, IP address, gateway, and DNS configuration.

On Windows, search the system settings for network troubleshooting or advanced network settings. On macOS, review the Network section in System Settings and confirm the Ethernet interface is active and connected.

The exact menu names may change as operating systems are updated, but the main goal is to confirm that the device recognizes the Ethernet adapter and receives valid network information.

9. Update or Reinstall the Network Adapter Driver

Outdated, corrupted, or incompatible network adapter drivers can prevent Ethernet from working correctly. Check for operating system updates and network adapter driver updates.

On a Windows computer, the network adapter can usually be found in Device Manager. You may be able to update the driver, disable and reenable the adapter, or uninstall the adapter and allow Windows to reinstall it after restarting.

For USB Ethernet adapters and docking stations, check the equipment manufacturer's support page for compatible drivers and firmware.

Driver updates are more likely to help when the problem began after an operating system update, hardware change, docking station change, or adapter installation.

10. Check Whether the Device Has a Valid IP Address

An Ethernet connection can show a physical link while still failing to provide network or internet access. This often occurs when the device does not receive a valid IP address from the router or network server.

Common signs include:

• Ethernet connected but no internet
• Unidentified network
• Self assigned IP address
• No default gateway
• Connection limited or unavailable

Restart the router and connected device, then renew the network connection. Confirm that automatic IP address assignment is enabled unless the network intentionally uses static IP addresses.

If other devices also cannot access the internet, the problem may be the router, modem, internet service, or network configuration rather than the Ethernet cable.

11. Check the RJ45 Terminations

If the Ethernet cable was made from bulk cable, the problem may be at one or both RJ45 terminations. The conductors must be arranged in the correct wiring order, fully inserted into the plug, and properly contacted by the plug pins.

Ethernet cable is normally terminated using either T568A or T568B. Both standards can work, but the same wiring standard should normally be used on both ends of a straight through Ethernet cable.

T568A Wiring Order

1. White and green
2. Green
3. White and orange
4. Blue
5. White and blue
6. Orange
7. White and brown
8. Brown

T568B Wiring Order

1. White and orange
2. Orange
3. White and green
4. Blue
5. White and blue
6. Green
7. White and brown
8. Brown

T568B is widely used in North America, but either standard may be used when both ends are wired consistently and the installation requirements are followed.

Common termination problems include:

• Conductors arranged in the wrong order
• Different wiring standards used on each end
• Split pairs
• Conductors not fully inserted
• Plug pins not contacting the conductors
• Jacket not secured inside the connector
• Wrong plug for the conductor size
• Wrong plug for solid or stranded conductors
• Pass through conductors not trimmed correctly
• Damaged conductors caused by stripping or crimping

12. Make Sure the Conductors Reach the Front of the Plug

When terminating an RJ45 plug, each conductor should extend fully into the connector so the metal contacts can pierce or contact the conductor properly. Look through the clear plug body and confirm all eight conductors reach the front.

The outer cable jacket should also extend into the plug far enough to be held by the strain relief. If only the individual conductors are secured, movement can pull them away from the contacts and cause an intermittent or failed connection.

Explore our RJ45 modular plugs for compatible Ethernet cable termination options.

13. Test the Cable With an Ethernet Cable Tester

A basic Ethernet cable tester can quickly identify open circuits, shorts, crossed conductors, reversed conductors, and incorrect wire mapping. Connect the main tester unit to one end of the cable and the remote unit to the other end.

For a correctly terminated straight through cable, the tester should show pins 1 through 8 in the same order at both ends.

A cable tester can help identify:

• Open conductor
• Short circuit
• Crossed wire
• Reversed pair
• Incorrect pin order
• Missing connection

More advanced certification testers can also measure cable length, insertion loss, return loss, Near End Crosstalk, and whether the installed channel meets a specific cable category.

A simple continuity test is useful for confirming wire mapping, but passing continuity alone does not prove that the cable meets Cat5e, Cat6, Cat6A, or another performance standard.

14. Check the Cable Length

The recommended maximum channel length for most twisted pair Ethernet categories is 328 feet, or 100 meters. This typically includes up to 295 feet, or 90 meters, of permanent cable and 33 feet, or 10 meters, of combined patch cables.

Longer cable runs may experience increased signal loss, reduced performance, unstable connections, or failure to establish a link.

If the cable must travel beyond the recommended channel length, use a network switch, Ethernet extender, or fiber optic connection rather than simply adding more copper cable. Review our guide on how to extend Ethernet cable for more information.

15. Inspect the Cable for Physical Damage

A cable can look normal from a distance while the internal conductors are damaged. Inspect the full cable run where accessible.

Look for:

• Kinks or sharp bends
• Crushed sections
• Cuts or exposed conductors
• Staples through the jacket
• Overtightened cable ties
• Damage near the connector
• Water intrusion
• UV damage outdoors
• Rodent damage
• Excessive pulling tension

A kink, staple, or crushed section can change the cable geometry and damage the twisted pairs, which may affect signal performance even when the cable still passes a basic continuity test.

When pulling cable from a box, maintain a steady pull and avoid sharp bends or excessive force. See our guide to pulling Ethernet cable from a box for installation tips.

16. Check the Wall Jack and Patch Panel

If the connection passes through a wall jack or patch panel, test each part of the channel. The cable may be correctly terminated at the RJ45 plug while the keystone jack or patch panel connection is loose or incorrectly punched down.

Check that:

• The conductors are seated fully in the insulation displacement contacts.
• The same T568A or T568B wiring standard is used throughout the channel.
• The wire pairs remain twisted close to the termination point.
• No conductors are cut, loose, or placed in the wrong slot.
• The patch panel port matches the wall jack being tested.
• The patch cables at both ends are known to work.

To isolate the permanent cable, test directly between the wall jack and patch panel or use a cable tester designed for installed cable runs.

17. Confirm the Plug Matches the Cable

Not every RJ45 plug is compatible with every Ethernet cable. A plug may be designed for a specific conductor size, cable outside diameter, conductor type, or cable category.

Compatibility issues may occur when using:

• A stranded plug on solid cable
• A solid plug on stranded cable
• A plug that does not support the conductor diameter
• A small cable plug on a large outside diameter cable
• An unshielded plug on a shielded installation
• A standard plug on cable with a spline or thick insulation

Always confirm the plug specification before terminating the cable. The conductor gauge alone does not guarantee compatibility.

18. Check for Electrical Interference

Ethernet cable installed too close to power wiring, motors, generators, fluorescent lighting, transformers, and other electrical equipment may experience interference.

Twisted pair Ethernet cable is designed to reject common noise, but excessive interference or poor installation can still reduce performance.

Maintain appropriate separation from electrical wiring, avoid long parallel runs next to power cables, and cross power wiring at approximately 90 degrees when necessary.

In high interference environments, a properly installed shielded Ethernet system may provide additional protection. The cable, connectors, patch panels, and grounding method must all be compatible for the shielding to work correctly.

Learn more about interference between twisted pairs in our guide to Near End Crosstalk.

19. Make Sure the Cable Is Rated for the Environment

Indoor Ethernet cable should not be used outdoors or underground unless the cable jacket is specifically designed for that environment. Moisture, sunlight, temperature changes, and direct ground contact can damage an unsuitable cable.

Outdoor or direct burial cable may be needed for:

• Exterior security cameras
• Detached buildings
• Gate systems
• Outdoor wireless access points
• Underground conduit
• Direct burial installations

Water intrusion can cause corrosion and electrical performance problems. If an outdoor cable worked previously and then failed, inspect the cable and termination points for moisture.

20. Check Whether the Cable Is Copper or Copper Clad Aluminum

Solid bare copper Ethernet cable provides better conductivity and more reliable performance than copper clad aluminum cable. Copper clad aluminum, commonly called CCA, uses an aluminum conductor with a thin copper coating.

CCA cable has higher electrical resistance and may be more prone to voltage drop, heating, conductor breakage, and performance problems, especially in Power over Ethernet applications.

For dependable structured cabling and PoE installations, use cable with 100 percent copper conductors that meets the required category and safety standards.

Ethernet Cable Connected but No Internet

If the device shows that Ethernet is connected but there is no internet access, the cable has likely established a physical link. The problem may instead involve the router, modem, internet service, IP address, gateway, DNS settings, or network authentication.

Try the following:

1. Restart the modem, router, and connected device.
2. Check whether other wired or wireless devices have internet access.
3. Confirm the device received a valid IP address.
4. Disable and reenable the Ethernet adapter.
5. Run the network troubleshooter.
6. Check for a service outage.
7. Confirm the router WAN connection is active.
8. Contact the network administrator or internet provider if the issue affects the full network.

If local network devices are accessible but websites are not, the issue may involve the internet connection or DNS rather than the Ethernet cable.

Ethernet Not Working but WiFi Works

When WiFi works but Ethernet does not, the internet service and router may still be functioning normally. Focus on the wired side of the connection.

Check the Ethernet cable, router LAN port, computer Ethernet adapter, wall jack, patch panel, and network settings. Try a known working patch cable directly between the computer and router to bypass the permanent cabling.

If the direct connection works, the issue is likely within the wall jack, permanent cable, patch panel, or one of the patch cables.

Ethernet Cable Not Working After Crimping

If the cable stopped working immediately after installing RJ45 plugs, the termination is the most likely cause.

Check for:

• Incorrect T568A or T568B order
• Different wiring patterns on each end
• Conductors not reaching the front of the plug
• Improperly crimped contacts
• Wrong plug for the cable
• Conductor insulation preventing contact
• Broken or nicked conductors
• Pass through wires not cut flush
• Cable jacket not secured by the plug

Cut off the failed plug and terminate the cable again using a compatible connector and crimping tool. Test the finished cable before placing it into service.

Ethernet Cable Not Detected on a Gaming Console

If an Xbox, PlayStation, or another gaming console does not detect the Ethernet cable, begin with the same physical checks used for a computer.

1. Reconnect the cable until it clicks.
2. Check the router or switch link light.
3. Restart the console and router.
4. Try another router port.
5. Try a known working Ethernet cable.
6. Run the console's built in network connection test.
7. Confirm the console is configured for a wired connection.

If another device works with the same cable and port, the console's Ethernet port or network settings may require further troubleshooting.

How to Tell Whether the Ethernet Cable Is Bad

A cable is more likely to be faulty when:

• Another cable works with the same devices and ports.
• The link light disappears when the cable is moved.
• The cable tester shows an open, short, or incorrect wire map.
• The cable has visible physical damage.
• The connection drops when the connector is touched.
• The cable fails on multiple devices.
• The cable cannot negotiate the expected speed.

For field terminated cable, replacing both connectors may resolve the issue. If the installed cable itself is damaged, the run may need to be repaired or replaced.

Final Thoughts

An Ethernet cable that is not working can be frustrating, but the problem can usually be isolated by checking one component at a time. Start with the link lights, reconnect the cable, restart the equipment, try another port, and test a known working cable.

If the issue began after terminating bulk cable, inspect the T568A or T568B order, verify the conductors reach the front of the plug, and test the cable with a cable tester. For permanent installations, also inspect the wall jack, patch panel, cable length, and physical cable run.

When a cable continues to fail across multiple devices and ports, replacement is often the most reliable solution.

Explore our Bulk Ethernet cable, RJ45 plugs, and networking tools for new installations, repairs, and troubleshooting.

Happy Cabling!