Outlook Express error. The message could not be sent because one of the recipients was rejected by the server. Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79

Outlook Express error. The message could not be sent because one of the recipients was rejected by the server. Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79

Answer: This is authentication related error in outlook express. To solve this error you can follow below steps.

1) open your outlook express and click on tools
2) Select accounts
3) mail tab
4) select your mail profile then click properties
5) Click servers tab
6) put a checkmark on my outgoing server requires authentication
7) CLose outlook express and start again.
8) Try to send an email

Please leave your comments if this helps.