What it means
Windows Network Diagnostics shows this when your PC is plugged into the router by cable but did not get a working IP address from it. Without a valid address the PC cannot talk to the router or the internet. A related message, "The default gateway is not available", means the PC can't reach the router at all.
Common causes
- The router has a temporary glitch and is not handing out addresses
- A loose or faulty Ethernet cable, or the cable is in the wrong router port
- The PC is set to a manual (static) IP address that doesn't match your network
- Corrupted network settings on the PC
- An out-of-date or damaged Ethernet adapter driver
- VPN or security software interfering with the network adapter
How to fix it
Work down the list. Each fix is safe to try before moving on to the next.
FIX 01Restart the modem, router and PCEASY
- Unplug the router's power, then the modem's power.
- Wait about 30 seconds.
- Plug the modem back in and wait until its lights stop blinking.
- Plug the router back in and wait a few minutes.
- Restart the PC with
Start > Power > Restart.
Why it helps: The router hands out IP addresses; a restart clears glitches that stop it doing so.
FIX 02Check the cable and portsEASY
- Make sure the Ethernet cable clicks firmly into both the PC and the router.
- On the router, use a LAN port, not the port marked
InternetorWANthat connects to the modem. - Try a different LAN port on the router.
- Try a different Ethernet cable if you have one.
Why it helps: A bad cable or wrong port is one of the most common causes.
FIX 03Run the Network and Internet troubleshooterEASY
- Open the
Get Helpapp in Windows 11. - Run the
Network and Internettroubleshooter. - Follow any fixes it suggests, then test the connection.
Why it helps: The troubleshooter can reset the adapter and fix common address problems automatically.
FIX 04Renew the IP address with Command PromptMEDIUM
- Select
Searchon the taskbar, typeCommand Prompt, selectRun as administrator, thenYes. - Type
netsh winsock resetand press Enter. - Type
netsh int ip resetand press Enter. - Type
ipconfig /releaseand press Enter. - Type
ipconfig /renewand press Enter. - Type
ipconfig /flushdnsand press Enter. - Restart the PC.
Why it helps: These commands reset the network stack and ask the router for a new address.
FIX 05Set IP and DNS to automaticMEDIUM
- Open
Settings > Network & internet > Ethernet. - Next to
IP assignment, selectEditand chooseAutomatic (DHCP), thenSave. - Next to
DNS server assignment, selectEditand chooseAutomatic (DHCP), thenSave. - If your workplace or provider gave you a fixed IP address on purpose, check with them before changing it.
Why it helps: A manual address that doesn't match your router stops the connection from working.
FIX 06Check the address Windows receivedMEDIUM
- In Command Prompt, type
ipconfigand press Enter. - Look under your Ethernet adapter for
IPv4 AddressandDefault Gateway. - An address starting with
169.254means the PC did not get an address from the router; restart the router and check the cable again. - If
Default Gatewayis blank, the PC cannot see the router.
Why it helps: This confirms whether the PC is actually getting an address from the router.
FIX 07Reinstall the Ethernet driverADVANCED
- Before you start, download the latest Ethernet driver for your PC model from the maker's website, using another device and a USB drive if needed.
- Select
Search, typeDevice Managerand open it. - Expand
Network adapters, right-click your Ethernet adapter and chooseUninstall device. - Check
Attempt to remove the driver for this device, then selectUninstall. - Select
Start > Power > Restart. Windows should reinstall the driver. - If it doesn't, install the driver you saved.
Why it helps: A damaged driver can stop the adapter from getting an address.
FIX 08Use Network resetADVANCED
- Warning: this removes and reinstalls all network adapters and resets network settings. You may need to reinstall VPN software and re-enter Wi-Fi passwords.
- Open
Settings > Network & internet > Advanced network settings > Network reset. - Select
Reset now, thenYes. - Wait for the PC to restart, then test the Ethernet connection.
Why it helps: Network reset is Microsoft's last-resort fix for stubborn network settings problems.
Check it's fixed
Settings > Network & internetshows Ethernet asConnected.ipconfigshows a normal IPv4 address (not starting with 169.254) and a Default Gateway.- Websites load in your browser.
When to get help
If another PC also fails on the same cable and port, the router or modem may be faulty, so contact your internet provider or the router maker. If this PC fails on every network, a repair shop can test its network port.
Questions
What does "Ethernet doesn't have a valid IP configuration" mean?
Your PC is plugged in by cable but did not get a working network address from the router, so it cannot get online.
What does "The default gateway is not available" mean?
Your PC can't reach the router. Restarting the router and PC, checking the cable, and updating the network driver usually fixes it.
Why do I have a 169.254 IP address?
Windows gives itself a 169.254 address when it can't get one from the router. Fix the router connection and renew the IP address.
Related fixes
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