Device offline?

I have 2 NVR systems with 14 cameras, I can view the cameras just fine and alerts on mobile app, but I can’t see he cameras live. Reboot NVR’s and iPhone, still no luck.

After two days of being offline, all cameras came back online Sunday morning. Any known server issues?

Mine was doing that allot lately and also freezing and taking a long time to load. Found out i had to reboot my network routers.