Training plan disappeared

We're having an issue with a training plan that suddenly disappeared.

About mid-way through the plan and after synchronising a workout post-run (iPhone with 245 Music), the training plan just vanished. The next three workouts are still visible in the calendar, but when opening the training plan page on the Garmin Connect mobile app, the current training plan does not show up anymore and a new one would have to be chosen. Additionally, the previous one, which has been finished successfully, is also not listed anymore. Reinstalling the mobile app did not solve the issue.

Furthermore, if visiting the Garmin Connect webpage, we are unable to view the training plan page and simply get an error message stating "Sorry, we're having trouble with this page".

Did anyone experience something similar? Help is much appreciated as it is super frustrating.