I got that message when my android phone was looking for my house's router. So I switched it to the MTH network and it worked for awhile.
I got a new engine and whenever it was moving, I started seeing that message again? The phone wouldn't talk to the engine or even the tiu. It ended up to be that the engine was killing the signal on the rails. It was easy for me to troubleshoot as it appeared with the new engine.
So, how is your signal strength on the rails?