Cannot connect to servername. You must use the same version for the Backup Exec server and the Backup Exec Administration Console.
Figure 1

The issue is caused because of any of the following two reasons.
1. Backup Exec Service Account lacking few privileges in the Group Policy which leads to this error.
2. The Backup Exec Service Account credentials are not updated properly in BEUTILITY.
RESOLUTION 1:
1. Verify the Backup Exec Service account is provided the necessary privileges in Group Policy management as per the following article.
Once the necessary privileges are provided, perform a Group Policy update on the server and perform a server reboot. After the server reboot is done, launch Backup Exec.
RESOLUTION 2:
If the steps mentioned in Resolution 1 does not resolve the issue, perform the following:
1. Navigate to C:\Program Files\Veritas\Backup Exec and launch the application BEUTILITY.
2. Stop all Backup Exec services and update the service account. Changing service accounts details.
3. After updating the service account details, start all Backup Exec services and then launch the Backup Exec Console.
The Console should launch successfully after the service account details are updated.
Cannot connect to servername. You must use the same version for the Backup Exec server and the Backup Exec Administration Console. Figure 1 