MARVEL Tsum Tsum will be disconnected if you had pressed the Home button, accessed another app, or checked push notifications. While in a session, please play through it without accessing anything else. Please also play in an area with a stable network connection.
These are some situations that could have affected your connection:
1. Connectivity can be spotty when travelling on public transportation.
2. Having multiple apps open at a time can cause issues.
3. Device being used has specifications outside of the recommended ones.