Installing 20.4 unable to authenticate with the user and password

Veritas support has been absymal on this. I have been speaking with several technicians for the past two weeks and none of them have provided any resolutions. 

I am trying to update Backup Exec 16 to 20.4 as standalone.

The serever passes most of the enviroment checks successfully but has a warning that the current user does not have permissions to log on to SQL server instances that have a designation of '**' even though the account i am logged in tohas full permissions to the SQL database, can act as part of the OS, log in as service account, and create tokens. 

The Backup Exec SQL Upgrade Check will randomly fail. sometimes it does, soemtimes it doesnt. I'm unsure why because the SQL instance is within the compatibility range at 2008 R2S2 and cannot be upgraded.

If i make it to the start instal screen, it will refuse the domain credentials we used to set up the backup server initially, suceed with local adin credentials, run for 30 minutes then fail again saying it was unable to authenticate with the user and password provided, which have been tested in RDP. 

Please someone help.