ARkit remote not working

Hi, I have followed the tutorials for setting up ARKit remote but something seem to have gone wrong.

When I play the game it works at first but then the app freezes after about 15 seconds and I need to restart the game. When playing a second time the app does not seem to connect to Unity, I get the camera feed in the app but without the game, in the editor the game window continue to display the same green screen with the 'Start Remote ARKit Session' button. If I restart Unity I can reproduce the same process, the remote work in the first session but freeze after 15 sec, after that I can't get another session working.

I have tried numerous combinations of restarting the app, reconnecting both via wifi and USB, etc, and rebuilt the app several times.

The app is built in debug mode, with dev build and script debug enabled.

Any ideas of what might be the issue? Many thanks!