We use exchange 2007 and out look 2010 client.
One of the staff emailed a person , who doesn't work in our organisation and they got the "Delivery is delayed to these recipients or distribution lists" message and I sent a test email to Arano@School.bristol.sch.org@ 2:00Pm and received a Delivery Delayed: Test email please ignore Mail Delivery Subsystem <MAILER-DAMON@Cypo.nps.org.uk @6:00Pm
Delivery is delayed to these recipients or distribution lists:
Subject: Test email plaese ignore
This message has not yet been delivered. Microsoft Exchange will continue to try delivering the message on your behalf.
Our spam filtering is hosted outside.
I am not sure where the problem lies , do I need to talk to our spam filterers. Please help to trouble shoot this problem