Thanks for the help. I am still missing something. (Sorry about dragging this on.) I did (and had already done) what you suggested and edited the SMPT server. I could add another account under "Description" and the "Server Name" but I could not add or modify an existing "in use by Account". Is that information necessary? Does it tell which email account (a given email address?) to use? If so, how can I change it? That did not solve the problem.
I still have a question when sending an email about the "From:" line in the header. It gives me the choice of three email addresses (including the one I use to receive email), all of which are not recognized by the server. I find not way to modify that information. Where does it come from? Where is it stored? I have looked all over but could not find it.
So, is there a way to tell the server to use one of these addresses or a way to change these addresses to one the server recognizes.