Likely causes
- Provider outage
- Loose or damaged WAN, DSL, fiber, or coax cable
- Authentication failure
- Modem or optical terminal problem
Quick checks, in order
Check the incoming cable
Confirm it is firmly connected and not sharply bent or damaged.
Restart in the correct order
Power the modem or optical terminal first, wait for stable line lights, then start the router.
Check provider status
Use mobile data or another connection to check for a regional outage.
Avoid a factory reset
A reset can erase provider credentials and make recovery harder.
Which other light is abnormal?
DSL or optical light is off
The incoming line is not established. Recheck the cable and contact the provider if it stays off.
Line light is normal but internet is red
Authentication or provider provisioning is the likely issue.
The red light started after moving cables
Reconnect the WAN and line cables to their original ports and restart the devices.
Stop and get qualified help when
Do not continue troubleshooting if any of these apply:
- The fiber cable is damaged or sharply kinked
- The power adapter or router is hot, sparking, or smells burned
Frequently asked questions
Will a factory reset fix a red internet light?
Not usually. It can remove working credentials, so use it only with provider instructions and configuration details available.
Can the router be connected while the provider is down?
Yes. Local Wi-Fi can still appear even when the external internet service is unavailable.
Did this guide move you closer to a solution?Your feedback will help rank the most useful checks.