In technical terms, the error translates to (0x8004230C). This indicates that Backup Exec’s AOFO (Advanced Open File Option) or the VSS infrastructure was unable to read one or more volumes on the target machine because the process lacked the necessary permissions.

Re-enter credentials for the System Logon Account and restart services. Locked Account Unlock the BESA account in Active Directory. Permission Denied Ensure the account is a member of the Local Administrators group on the target server. VSS Service Error vssadmin list writers in CMD to check for failed application writers. To help narrow this down, are you seeing this during a backup job or while trying to install a remote agent Solved: Backup exec access is denied - Experts Exchange

Sometimes, VSS operations time out due to high I/O load.