Hi, I'm using a H200 hub with 4 C420 cameras (+T100 movement sensors) connected.
All going well, this morning it captured normal movements etc. But I noticed later in the day no notifications were reaching my phone.
In the past when I've seen this I've restarted my phone which fixed things. But not today...

I poked about some more (and with another mobile device) and reaslised the hub wasn't responding normally. It let me reboot via the app, but still no good.
I couldn't see any recordings and the cameras showed connected but I couldn't view them. I powered the hub off/on, no good. Powered off and left for a while but still no good after restarting. Hub showed green LED but was still unresponsive. 

My internet (and wifi) was rock solid and working normally on other devices so I didn't want to reboot that, instead I just turned the wifi off/on and this time the hub and cameras have come back to life. 

Just posting this in case it helps anyone. You would think the 3 hub reboots would have been enough to give the wifi a kick if there was a problem there, but it seems not. Wifi was fine with all other devices.

FAO TP-Link: In the middle of this I tried looking at the TAPO Knowledge Base for the 'Smart Hub' troubleshooting tips and found it was all blank!
The first items are there, but for me, from the Smart Hub onwards things are all blank?
https://community.tp-link.com/en/smart-home/kb/2360