I just had the issue while attempting to migrate to a new Cloudron restore, at the step of restoring a full backup and this despite following exactly the steps in Cloudron guide for restoring backups.
I quickly solved it through:
Reviewing unbound service status shows everything looked ok
I had a doubt about the private key password being good, as the backup configuration didn't clarify that in the UI.
I just put my private key password again, and attempted the restore button, this time it works.
So it's good to mention maybe in the guide that the private key password should be double checked even if using a preexisting backup configuration generated from the previous Cloudron instance.
