I've had issues with Duplicity not performing backups when a single backend is down (despite it being set to continue on error). In my case an SFTP server lost

I've had issues with Duplicity not performing backups when a single backend is down (despite it being set to continue on error). In my case an SFTP server lost its IPv6 routing so Duplicity couldn't connect to it; rather than give up on that backend and only use the other server it just gave up entirely.