The plot thickens...
This is an automatically generated Delivery Status Notification
Delivery to the following recipient failed permanently:
[email protected]
Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 553 553 sorry, that domain isn't allowed to be relayed thru this MTA (#5.7.1) (state 14).