This error will arise the below scenarios have done.
1.The user name and pass word is incorrect
2.We don't have an user account with this name
To resolve this error we need to create a new login user using server management studio.Here i will show how to create a user with images
After login in to the server with windows authentication ,we have to collapse the Security menu then right click on login and select New login.We can see the below image how we doing this process.
Give the login name and select the sql server authentication ,then give password for user.After complete this process we can give some roles to this user by selecting server Roles which on top most left side menu item.By default the public role has assigned to user here.
Finally we can see the created user under login tab as in the below screen.By using created credentials we can login into sql server