SCCM BACKUP PROCESS - ERROR - THE USER NAME OR PASSWORD IS INCORRECT

In the backup process, I'm getting the error "Cannot create \share\Backup\CM1\AdminUIContentStaging, [error code: 1326, error message: The user name or password is incorrect.]" only during the backup process. The database backup is working fine without any issues.

The system users have full control on the share. Since it's the system user that performs this action, I can't understand why it's giving the error message mentioned above.

I have SCCM version 2303.