If this is occurring on the internet, do you notice any lights change on the router at all?
Do you need to re-boot the router to get the connection working again?
Can you post the network log from the router for me to check over please? To do this type in 192.168.0.1 in the address bar, no need to sign in, on the top right you will see router status. Within here you will have downstream, upstream and network log. You can copy and paste this information, that would be great.
It may be worth creating a Broadband Quality Monitor to check the performance of the connection. If you do set up the BQM make sure that you go into your router settings > Advanced Settings > Ping > and tick Respond to ICMP echo requests sent to WAN IP.