routerlogin.net spins until router is rebooted

Hello.

Issue

Device: Nighthawk C7000 V2 (modem/router combo)

WiFi: Working

Wired: Working

Readyshare: Working

Routerlogin.net NOT working - Browsers (tried Mozilla, Edge, IE) "spin" until next reboot of device.

Workaround

Reboot device, then all the above work for a while.  I notice the issue every couple of days.

Fix?

While rebooting the router does resolve the issue, I don't believe I should need to reboot every couple of days.

I can't find a resolution. Does anyone else have this issue OR know of a fix?