Network Connection

On the app and network box it says all the devices are connected with excellent connection but my tv constantly says not connected and I have to unplug and restart it every time I turn it back on because it says not connected and doesn't find a connection until I unplug it and turn it back on. I thought it was a problem with my tv and after getting a new tv months later this issue has started back up and happens with several of the TVs in my house so I know it's not a tv problem anymore why is this occurring and what can stop it from keep happening?