Hi @Faye Entienza - Thank you for reaching out to us!
Regarding the issue, if a backup is triggered while the other backup was in progress, then the backup job is going to fail. But if the previous backup operation is completed, then the new backup job completes with success.
To resolve your issue, follow the steps from the troubleshooting guide - https://learn.microsoft.com/en-us/azure/backup/backup-azure-mars-troubleshoot#job-could-not-be-started-as-another-job-was-in-progress
Wait for sometime and If issue persist, try to stop the backup job by running the cmdlets documented here - https://learn.microsoft.com/en-us/powershell/module/az.recoveryservices/stop-azrecoveryservicesbackupjob?view=azps-6.4.0
Hope this helps!
Feel free to ping if you need further assistance in this matter.
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