Backup domain controller

Hi dear All. i use Symantec Backup exe version 15. i have domain controller on windows server 2012 R2 and windows server 2016 r2. after adding server to symantec click -establish trust- like error. i search on google but cannot find

The job failed with the following error: Failed to log on to Microsoft Windows.

Ensure that your logon credentials are correctly entered and that they meet the following minimum requirements to log on to a Windows computer:

   - The credentials used are a member of the Backup Operators group.

   - For Windows Vista/2008 and later, the credentials have the Log on as a batch job privilege.

Additional privileges may be required to access resources on the Windows computer."