Backup Exec permission fail on Isilon backups

I am having a hard time with permission issues with Isilon and Backup Exec. I upgraded to version 20.3. Whenever I run a backup job on Isilon (The server was added by using File Server/NDMP data server), I get the following error:

Backup Exec could not log on to the server with the logon account specified for it. The logon account does not have valid credentials. Ensure that the user name and password are correct in the logon account

For the life of me, I dont understand why this issue happens. When I go into the job, I can see the files and folders with the main service account for Backup Exec. I have granted the main account with full control of the folders on the Isilon, but I still get this **bleep** error of permissions. Has anyone come across this?