I keep receiving this email error when trying to connect to my personal email. 0x800CCC79

To fix this problem:

Open Outlook Express, and click Tools
Then click on Accounts
Then click on your email connection and click Properties
Then click Advanced
On this screen remove the checks from the boxes This server requires a secure connection for both Outgoing mail (SMTP) and Incoming mail (POP3).
Make sure 'this server requires authentication' is checked

I followed this advice and it still does not work. The error states the message could not be sent because one of the recipients was rejected by the server. The rejected email address was <XXXXXXX>. Subject 'xxxxxxxxxx' Account xxxxxxxxxxxxxx@bellsouth.net. Server 'mail.bellsouth.net'. Protocol SMTP.Server Response: '550, Error Number 0x800CCC79

Have tried to send to yahoo, gmail and work account it does not work. Sending to bellsouth recipient worked.......HELP