Router fiber optic light is red no internet connection

This guide walks through seven easy methods to troubleshoot a red router light and get your connection working again, from checking service status and cables to restarting equipment, updating firmware, resetting the router, and knowing when to contact your ISP. A red light on your router usually means the device has lost its internet connection, is failing to authenticate with your provider, or has detected a hardware or service problem. In many cases, the issue is temporary and can be fixed with a few basic checks before you call support. [pdf]