Clear MARS backup warning: Validate
I just noticed this after a recent update of the backup agent version on the protected server. It's easy to miss so I searched around, apparently there are new passphrase requirements with the update. You will need to know the passphrase when you initially registered the server to the vault and enter it into a CLI window that appears by clicking the little link in the message at the top of the Microsoft Azure Backup UI on the protected server here: MARS-validate
Gotta love MS always always finding different places to put stuff in the UI.