When there is a difference between the External Server URL, and the one you use configuring the iPhone Verse devices, you will see that the connection is now broken using version 12.0.3
Introduced in Verse iOS 12.0.3, the server uses the url defined in the Server Document in the Traveler tab. The application now checks the External Server URL. If the server URL received from the server does not match the URL entered by the user, the app uses the server URL instead.
In my case, that URL doesn’t exist anymore and we forgot to change it in the server document.
After changing the External Server URL in the Server document to the correct one, and restarted the Traveler task, the connection was set again.