vCenter File-based backup failed with "Access to the backup server is denied. Check your credentials"

Products

• VMware vCenter Server 7.0
• VMware vCenter Server 8.0

Issue/Introduction

• The File-based backup of vCenter Server does not work
• In vCenter UI there is alarm about the failed backup job
  
  Feb 08 23:59:11 <FQDN-VC> vpxd[7179]: Event [575229570] [1-1] [2025-02-08T23:59:11.483369Z] [vim.event.AlarmStatusChangedEvent] [info] [] [] [575229570] [Alarm 'Backup job status' on Datacenters changed from Green to Red]
  
  
• In /var/log/vmware/applmgmt/backup.log there may be similar messages:
  
  2025-02-08T23:15:09.523 [0] [MainProcess:PID-59523] [Scheduler::ExecScheduleRun:Scheduler.py:138] ERROR: Failed to issue the Schedules.run request. Exception: {messages : [LocalizableMessage(id='com.vmware.applmgmt.backup.plugin.unauthorized', default_message='Access to the backup server is denied. Check your credentials.', args=['Plugin error occurred. ErrCode: 1, Args: ()'], params=None, localized=None)], data : None, error_type : None}
2025-02-10T23:15:09.761 [0] [MainProcess:PID-55808] [Scheduler::ExecScheduleRun:Scheduler.py:138] ERROR: Failed to issue

Environment

VMware vCenter Server 7.0.x
VMware vCenter Server 8.0.x

Cause

The credentials of backup server was changed that caused the configuration in vCenter Server File-based backup is incorrect. Then the backup job failed in vCenter Server because it can not authenticate with backup server. 

Resolution

To resolve the issue:

• Make sure the backup server (etc, SMB, NFS, SFTP) is still online and the credentials permissions are correct.
• Correct the credentials configuration in VAMI backup of vCenter Server.
• After that manually run File-based backup again in vCenter VAMI.