with my internet provider, I have a short internet interruption every 24h. I used Duplicati 126.96.36.199_beta_2021-06-17 as a service. Duplicati always hangs after this interruption. I have to stop Duplicati.Server.exe and two DuplicatiWindowsService.exe in the task manager and restart the Duplicati service.
The backup destination is mounted via ftps. I have noticed this with other backups as well, that Duplicati tends to hang. There should be an instance in Duplicati that checks if data is still being moved and possibly restarts the process.