Recovery is already running
Snapattic allows one recovery at a time. This keeps the active account, read-only mail connection, local progress, and saved-photo ledger bound to the same recovery.
If you want to use a different account, return to the active recovery and choose Stop. Wait for Snapattic to confirm that progress is saved, then change accounts. You can reconnect to the first account later and resume without starting its recovery from scratch.
Do not force-quit solely to switch accounts. If the app is already closing, allow it to finish closing the read-only connection before opening it again.