I am unable to send emails with TIF/TIFF files attached outside our organisation. Emailing them internally works fine, so my suspicions are with the ClearSwift MailSweeper for SMTP. The following is logged in the event log
Network I/O error 10054 (0x00002746) encountered when sending message data to <mailserver>
I also receive regular emails stating that the email is delayed (see below);
Your message has been delayed and is still awaiting delivery to the following recipient(s):
I/O error encountered
during command: (message data)
Any help greatly appreciated.