If you're trying to add MS SQL Web or Standard to your server that uses Plesk, you need to create a separate administrative user for SQL Server
- Connect to your Windows server with Remote Desktop Connection.
- From the Start Menu, open SQL Server Management Studio.
- Connect to your database as your Remote Desktop user. SQL Server Management studio should load this automatically.
- On the folder tree on the left, expand Security.
- Right-click the Logins folder, then click New Login.
- Type the username you want to create into the Login name field.
- Select SQL Server Authentication.
- Enter and confirm a password for that user.
- Clear the check box for Enforce password policy to make sure that you are not having to reset your SQL Server password frequently.
- Click Server Roles on the left-hand menu.
- Select the box for sysadmin.
- Click OK.
You can now use this admin user for creating and managing your SQL Server databases.
Next step