We have a backup vault with 18 azure vm's registered to it, to backup some folders on each machine every night. This has been running fine for months now, with the occasional update of the backup agent.
Now, since yesterday night, the backup on 14 servers is failing with the message:
Microsoft Azure Backup encountered an internal error. Wait for a few minutes and then try the operation again. If the issue persist, please contact Microsoft Support (0x1FBD1)
What I've tried
-a manual backup: this failes with the same error code
- restarted one of the servers, and tried a manual backup; also failes
- created a new backup vault, unregistered one of the servers and tried registering it to the new backup vault. This takes a very long time, more then usual when setting up the backup, and then failes trying to set the encryption keys.
Last night all backups failed again, except for the same 4 that have succeeded.
Does anyone have a tip what to do or what to look for?