554 validating sender Onlinesex comchat
Please contact your system administrator so they can review the matter and contact us, if necessary.
We were unable to deliver your email because the potential recipient does not have sufficient free space in their inbox.
Due to an incorrect configuration, email reception has been refused.
Please contact your administrator who should correct the server configuration based on our recommendations.
I'm using a desktop version of Outlook 2007 and connecting through my ISP. means that the recipient email server believes that the email address does not exist at the destination domain, and therefore has no way to deliver it.
Unless you simply made a typo in the email address, this is not something that you can fix, and must be addressed at the other end.
Would you like to answer one of these unanswered questions instead?