Hey there, sorry for the delayed reply.
This appears to be a connection issue. Are you still receiving the error regularly?
Even if you have full reception it’s possible for there to be an issue with the game server or somewhere in the connection between us.
If the issue is between us somewhere then the connection won’t show up in the game server status or your reception bars on your phone.
Usually these sorts of issues are fixed quite quickly by the company responsible and it’s temporary.