Troubleshoot error message 0x800CCC79

Symptom

You can receive email message but can’t send email using DomainsFoundry SMTP. When you try sending Outlook returns an error message similar to the one shown below;


The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was ”. Subject: ”, Account: ”, Server: ”, Protocol: SMTP, Server Response: ‘550 … Relaying Denied’, Port: 25, Secure (SSL): No, Server Error: 550, Error Number: 0x800CCC79

Cause

  • Your ISP maybe blocking access to SMTP over the default port 25. This means your Outlook is unable to connect to the SMTP server to send your email.
  • SMTP authentication may not be enabled in your email client.

Resolution

  1. Try changing the default SMTP port from 25. See [[How to change SMTP port number]]
  2. Check SMTP authentication is enabled in your email client.