From Veeam we are taking SQL Server backup

SQL Server Administration
1

Warning: [TDB]Unable to update SQL backupset for instance : Code = 0x80040e09 Code meaning = IDispatch error #3081 Source = Microsoft OLE DB Provider for SQL Server Description = The UPDATE permission was denied on the object ‘backupset’, database ‘msdb’, schema ‘dbo’.

I opened the respective SQL Server. Checked whether the user is exist or not in the SQL Server.. In the SQL Logins i found that "ABC\Domainusers" exist. what ever the configured ABC\abcadmin is under Domain users.

2

is the user present in msdb database?
I remember the veeam sql account must be a sysadmin on the sql server instance.