You need to back up the server to Azure

You have a server named Server1.
A Microsoft Azure Backup of Server1 is created automatically every day.
You rename Server1 to Server2.
You discover that backups are no longer created in Azure.
You need to back up the server to Azure.
What should you do?

A.
From the Azure Management Portal, modify the configuration of backup vault.

B.
On Server2, run the Add-WBBackupTarget cmdlet.

C.
On Server2, run the Start-OBRegistration cmdlet.

D.
From the Azure Management Portal, upload the Server2 certificate as a management certificate.

Explanation:
The Start-OBRegistration cmdlet registers the server with using the vault credentials downloaded during
enrollment.
Question: What happens if I rename a Windows server that is backing up data to Azure?
backup vault and it will be considered a new server by Recovery Services, so the first backup operation that
occurs after registration will be a full backup of all of the data included in the backup instead of just the changes
since the last backup occurred. However, if you need to perform a recovery operation you can recover the data
that has been backed up using Recover from another server recovery option. For more information, see
Rename a server.
Azure Backup – FAQ
https://azure.microsoft.com/sv-se/documentation/articles/backup-azure-backup-faq/
Start-OBRegistration
https://technet.microsoft.com/en-us/library/hh770398(v=wps.630).aspx