The messesage could not be sent because the server rejected the senders email address

Verify your address it might be incorrect.

I have never seen an email address with two .coms...
One is usually sufficient.

That isn't a question. It is also not something that anyone here can sort because the problem is that the server doesn't recognise the address. In other words you need to check your spelling.

email address you are sending might be not correct or inactive

One problem is that the incoming (POP) mail server shown in the error message appears to be incorrect. The server address should be "pop.att.yahoo.com" (with a period between "att" and "yahoo"). The incorrect mail server address may interfere with authentication of the sender's email address, which is needed before the outgoing message is sent.

The "530 authentication" message indicates your outgoing (SMTP) server likely requires "server authentication". Also, the "Port 25" message indicates your email program is currently trying to send via Port 25, with no SSL; but Ameritech/Yahoo accounts appears to use Port 465 with SSL enabled.

See more on sever settings for "ameritech.net" users:
http://www.dslreports.com/faq/5535
https://motorola-global-portal.custhelp.com/app/answers/detail/a_id/61941/~/i886---at%26t,-bellsouth,-sbcglobal,-ameritech-email-settings

I would suggest you check the settings for your Ameritech email account in your email program. You may need to correct several settings. The steps to access account settings are somewhat different for various email programs (Outlook, Windows Live Mail, Thunderbird, etc.). You should be able to find guidance in the "help" section of your email program.

Try using ....outgoing.verizon.net.....and port 587 instead of 25(default).
From the "Tools" menu, select "Accounts."
Select your Yahoo! POP account and click the "Properties" button.
Click the "Advanced" tab.
Next to "Outgoing server (SMTP)," change port 25 to 587.
Click "Apply." Then click "OK" and "Close."

Hope this helps.
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Try checking the SSL checkbox for outgoing server.

Looks like their spam filter is stopping your mail.

the message could not be sent because it rejected as the the sender

the message could not be sent because it rejected as the sender