reconnect tvs

I don't understand how this works, my WiFi info & password saves in each tv but every single day when I turn the tv on I have to go into settings & connect it to it luckily I don't have to put in the password or info but it never stays connected & I don't know why! But it doesn't just do this to one of the TVs in our house it does it to all 4 of them.. WHY!?