I've found the same problem. The first time I logged into my Asmodee account, my party dissapeared, I create a new party with the same characters and I played the next mission because the progress of each character was saved. Then I restarted the app, I logged again into my Asmodee's account and my party dissapeared again but also the characters and all their progress!!! Now I will have to start again the path with a fresh party