Hello @Steve Gerbec Much appreciate your patience throughout the support tenure on Microsoft Q&A platform and with Azure technical support team.
"Sharing the summary of the issue for benefit of broader community"
Issue: Microsoft Azure Backup Server is failing online recovery point jobs for all servers.
Cause: The passphrase was missing/lost causing the online recovery points failures.
Resolution: Uninstalled MARS agent rebooted server and re-installed the agent.
Created a new Recovery Services Vault (RSV) and generated a new passphrase and registered the Microsoft Azure Backup Server (MABS) to the RSV.
Nesting through each protection group to ensure that it would get the setting of the new online location saved. Post these steps the online backups started working as expected.
Hope this helps others looking for solution to the similar issues.
@Steve Gerbec Thanks once again for your kind gestures.
Happy holidays!
If the response helped, do "Accept Answer" and up-vote it