a month ago
What does the bounce email say, (don't post any email addresses in your reply).
4 weeks ago
I have had the same problem for the past two days and I know of one other Sky user who has the same issue.
The email back comes from MAILER-DAEMON@yahoo.com with the subject Failure Notice and the message starts:
Sorry, we were unable to deliver your message to the following address. <email@example.com>: Unable to deliver message after multiple retries, giving up.