mail2.exchangedefender.com is scheduled for a migration this weekend to new hardware that has been fully provisioned.
Connectivity to the mail service for new mail is not expected to last beyond 5 minutes. However, the migration of the emails will take a few hours. This blog post will contain updates through the process. Again, we would like to reiterate that real time usage will not be affected, you clients will be seeing new email come immediately and send immediately.