Yashwanth G 0 Newbie Poster

Hi, I want to edit the sql server regestration. I want to change the Connection property from Windows authentication to Sql server authentication. But when I edit the sql server authentication with sa username and password, it gives error message saying that the registration has failed for user sa, not associated with trusted sql server connection. Please help me. I have also attached a screen short picture for your understanding about what i am doing.
Thank you.