You can troubleshoot the red light issue on the router by downloading the ‘My Spectrum’ app on your mobile device. To fix the red light on spectrum router, you need to enter the credentials in that app and then search for the internet troubleshooting tool. After that, look for the ‘My Account’ tab and search for the services option and click on it. Now, scroll down to find the equipment option and then click on experiencing issues and simply restart your modem. See if the problem has fixed.