Generally, Login failed in SQL , mean the user does not have elevated privileges to access a specific database.
Regarding your issue , When you add "xxxxx\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 databases.
Meanwhile, if you need to provide this account a full control on the Central Admin and PowerShell,you will need to do the following
- the user is added to Local Administrator group on all server in Farm.
- the user is added to Central Administration Farm Administrator Group.
- the user is added to Web Application Policy with FULL control.
- the user has access to SQL Server level and a
db_owner
and SharePoint_Shell_Access
for all SharePoint databases.
For more details check