Hello,
Please perform the following steps to resolve the issue:
1] Enable the Restrict Anonymous using following technote:
http://seer.support.veritas.com/docs/238618.htm
2] It may also due to a Backup Exec service account permission related issue.
Ensure that the Backup Exec service account is a member of Domain Admin and local Administrator group and remove it from all the other groups including Backup operator group.
1) Create a new user
Add the user to the local administrator and Domain Admin's group.
2) Start Backup Exec, create a Logon account with same username and password as that of newly created user .
You may refer to following:
-Start Backup Exec
-Select Tools > Wizards > Logon account wizard
-Add new logon account, type in the credential for the new account.
-Make this account a common logon account.
-Complete the wizard.
Refer to the following technote:
http://seer.support.veritas.com/docs/254246.htm
Thank You,
Shweta