First, you need to login to your sql server windows authentication mode.

Selecting Security

Right click on "sa" user, then select Properties.

Next, Select General

Entering your sql password, then click Status

Selecting Enabled login, then click OK button.
Right-clicking on your SQL Server, then select Properties

You need to change from "Windows Authentication mode" to "SQL Server and Windows Authentication mode", then click OK button.

Right-clicking on your SQL Server, then select Restart.

Entering your user and password, then connect to SQL Server.