If you notice a red light blinking on your router, it could be a result of a lack of communication between the router and your modem. You can follow the below-mentioned troubleshooting steps to get rid of the router blinking red issues:
Ensure that all the cables are properly connected to the router and there are no loose connections.
Restart the router by disconnecting the power adapter of the router from the electric socket and connecting it again after two minutes.
Check if the Ethernet cable connecting the modem and your router is in proper condition. If there are any physical damages to the cable, replace it with a new one.
If the issue still persists, reset the router by pressing and holding the router’s reset button for 10 seconds.