I am getting this error while trying to connect to the SQL Server.
Microsoft SQL Server Error: 18456
Can anybody tell me what the error code means?
If you're trying to connect using "SQL Server Authentication" then you may want to modify your server authentication:
Within the Microsoft SQL Server Management Studio, in the Object Explorer window:
Right-click on the server and click Properties
Go to the Security page
Under Server authentication, choose the SQL Server and Windows Authentication mode radio button
Click OK
Restart SQL Services