First of all try to check the connection of wires in the router. Try to turn off and on the router by unplugging the power cord, unplug the network cable from bothe end and turn the router on after a minute.
If it does not work try these
1. Open CMD or PowerShell and run as administrator.
2. Type the following commands
netsh winsock reset
netsh int ip reset
netsh advfirewall reset
ipconfig / flushdns
3. Restart your computer