"The Query for LogonAccount Failed" on BackupExec 2012

I've an error on the lower left corner of the UI displayed in a exclamation mark on a red triangule. When I put the mouse over it I the message "The Query for Logon Account Failed". (see file Error1.jpg)

Also the "Manage Logon Account" window display no logon account. Some times I create new logon accounts and it displays until I restart the BackupExec User Interface. (see Logon Account.jpg)

The backups are performing well, as it were created before the error started.

Is there a solution for this?

Thanks

João Nascimento