Generally, Login failed in SQL , mean the user does not have elevated privileges to access a specific database.
Regarding your issue , When you add `"MOJPORTAL\usr1"` in Farm Administrators group, it will have permissions and responsibility to can perform some administrative tasks in Central Administration on the farm, and this will require access to SharePoint Databases like configuration database,
So to avoid login failed or access denied issue ,you should make sure that :
- the user has access to SQL Server level and a `db_owner` and `SharePoint_Shell_Access` for all SharePoint databa…