We are currently aware of a problem causing email sent to customers' addresses to bounce. This also effects any domains customers may have hosted or registered on their accounts. An example of one of the returned messages that will be bounced to the sender can be seen below:-

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
me@privacy.net
SMTP error from remote mailer after RCPT TO me@privacy.net
host mx.core.plus.net [212.159.14.223]: 550-REJECTED:
The email address (me@privacy.net) is not valid on this 550 system.

Our network engineers are working on the problem as a priority and further details will be posted as they are made available.

Please accept our apologies for the inconvenience.

Kind Regards,

Bob Pullen
Customer Support