How to fix 0x800CCC6f in MS Outlook 2007


New Email
Getting 0x800CCC6f error message on outgoing mails for a Tiscali account.
Using MS Office 2007 and Windows XP.
Have checked all settings and Tiscali web-mail service works fine.
Any ideas on how to solve?.

Prior to this I was also experiencing outgoing mail being blocked by what I believe is a 'return receipt' stuck and won't let other mails be delivered.

EQ Admin

EQ Forum Admin
Staff member

If you still need help with the original issue please see this guide:

What is the full error message that you are receiving?

Is it possible that your computer has or recently had a virus or spambot installed?

The generic description and resolution for error 0x800CCC6f is:


The senders' SMTP e-mail address that is configured in Outlook and Outlook Express (POP3 or IMAP client) does not match an address in the Exchange directory and cannot be validated by the Internet Mail Service.


This resolution assumes the Exchange Administrator wants to retain the anti-spoofing configuration on the Internet Mail Service.

In Outlook Express, ensure the e-mail address entry (from the Tools menu, click Accounts , click the Mail tab, select the User name , click Properties , and then click the General tab) is the same SMTP e-mail address for the Exchange user located in the Exchange directory (under the Exchange user properties, E-mail addresses tab, SMTP address).

In summary some things that would be good to check are:

  • The full text of the error message
  • Are you on the Tiscali network when trying to send email through their servers?
  • Did your computer recently have a spam problem and get blocked?
  • Is an antivirus or firewall program on your computer blocking outbound port 25 connections?
You should be able to verify whether or not your email is being blocked by their servers for abuse/spam reason by calling the Tiscali technical support phone number at 0871 222 3311.

Please let us know if the above information helped to solve your problem and what the specific problem/fix was so that other people with the same problem in the future can benefit from the answers. :thanks: