smtp fails between two exchange 2003 servers on the same domain. (2003 server R2)

SMTP fails between two exchange 2003 SP2 servers on the same domain. (2003 server R2)

The first exchange 2003 server "mx1.abc.local" is hosting mailboxes for users at SITE A with email addresses @a.org

I have added a second exchange server for SITE B
exchange 2003 server mx2.abc.local is hosting mailboxes for users st SITE B with email addresses @b.org

I have define a SMTP "Connector" to forward all mail out via our isp a with an Address Space of *.
(same isp in both locations) with MX1 and MX2 selected as bridgehead servers on the conector.

I now have a queue of mail on MX1 for MX2 (emails to b.org) and a queue of mail on MX2 for MX1 (emails to a.org) . both queues are saing :
The remote server did not respond to a connection attempt.

We have a VPN between Site A and Site B and mx1and mx2 can ping each other.

Question 1
Do they need a connector/route  or is it some problem with the SMTP virutal servers ?

Question 2
Client at connecting to mx2 are getting sycronise errors with the Offline Address Book. Do I need to do anything to get mx2 to sync the Offline Address Book?

Thanks
Brian