When I logon after shutting down and starting up my phone the only way I can get connected to the mobile network is to dial a call. All I have to do is enter one number, press the dial button and after the first ring I am connected to the network and will be connected all the time until I logon off and then logon again. I had a S7 Edge about 10 days and it did the same thing. Returned it since everyone thought it was defective, but my S7 does the same thing. I am using TracFone on the Verizon network.