The Linksys router error 651 can be caused by the PC or modem. There could be something wrong while you are trying to connect your PC with the internet. Restart both your modem as well as the Router when you are trying to regain the connection. If again show error, Just dial Router Error Code toll-free number USA/Canada: +1-888-480-0288 and UK: +44-800-041-8324. We are 24*7 available. https://bit.ly/2SrEFRL