مراحل زیر را انجام دید :

  1. Start Enterprise Manager.
  2. Expand Microsoft SQL Servers, and then expand SQL Server Group.
  3. Right-click the server that you want to change to SQL Server and Windows authentication, and then click
    Properties.
  4. In the SQL Server Properties dialog box, click the Security tab, click SQL Server and Windows, and then click OK.
  5. When you are prompted to re-start the SQL Server service, click Yes.

مرجع :

https://support.microsoft.com/en-us/help/889615/you-may-receive-a-not-associated-with-a-trusted-sql-server-connection