first thing that comes to mind is maybe an address issue? or signal problem. I'm thinking it's a device/ app issue. Probably nothing with the WIU.
1) using the remote which you stated runs the engine, how strong is the track signal?
are you adding it on a test track with nothing else drawing power on it?
Does it show any other issues like missing the watchdog start-up issue?
2) what address is in the engine using the remote?
Is this address open in your IOS device app?
3) Can you easily reset your app in your IOS device and re-add your engines?
I had problems with missing software in an older Android and my DCS app kept crashing. I used another new device and that app worked fine. That old phone is finally had it with running my trains I guess. I had deleted stuff because the phone's memory was full. Now it doesn't work fully. I got tired of resetting the app trying to cure the issue as a workaround.
