
It wasn't easy, but I figured it out. No help from AT &T. I'd intended to post the solution, but I forgot.
There are several steps. I use Outlook Express. You may use a different email program that may require a different solution.
First off, log into your AT & T account. Find your way to your email account.
Click on 'options'. You'll see it on the upper right.
Now click on 'Mail Addresses' under the 'Management' heading.
Now click on 'Add'. Then enter the email address you want to be able to use as a sending email address. You will be sent an email to verify this address.
Now, back at Outlook Express. Click on 'tools', then 'accounts', then the email address you want to use and click 'Properties'.
Under the 'Servers' tab you'll need to make your Outgoing mail (SMTP) "smtp.att.yahoo.com".
At the bottom of the 'Servers' section check off "My server requires authentication".
Then click 'Settings'. Under Settings select 'Log on using'. Then enter your AT & T email address as the 'Account Name'. Enter your AT & T password in the 'Password' field. Click 'OK' and get outta there.
Now, click on the 'Advanced' tab. For 'Outgoing mail (SMTP) enter '465'. Put a check mark underneath that where it says 'This server requires a secure connection (SSL).
Hit 'OK' and you're done. You should now be able to send email using a non AT & T email address.
I know it sounds like an awful lot of bother. And it is a bother that AT & T should not make us go through. But it doesn't really take all that long. And after you get it done it works just fine.