Hope your problem is solved.
The specified settings worked for me as well. I received the error of “Invalid server” which you mentioned when I was using TLS. I changed the setting of email account as well to use this email as outgoing email.
Went to add the Yahoo domain again and was successful. Same error message with the SMPT port set to 587, it saved successfully when changed to 465. Will deal with adding a second sending email address in a different post, if necessary.