We had a different problem also related to above. I have an Exch 2000 Org with three sites, lets say site1 , site 2 and site3. Site1 is my main site with external sending. Site 1 and site 2 are Domian Controller sites. I added my connector between Exch 2007 and site 1, mail flowed between site 1 , site 3 and external, but not to site 2. Collapsed all the sites into the same Exch 2000 routing group, but the mail to site 2 sits in the "Unreachable Q". We are going to remove and recreate the Exch 2007 routing connector, see what happens. Any help, I see a number of posts with similar errors on google.

Hi, It probably won't help to recreate the routing group connector - you already have mailflow from 2007 to 2003 right? Can you telnet from the 2007 server to the 2003 server in site 2 on port 25? Leif

Yes, I can telnet to any site (Including from the new 2007 at site 1) on port 25. We did re-create the routing group on Friday, but still the same problem. Just to clear up something, the old mail servers are all Exchange 2000, the 2000 Exchange at site one is currently the smarthost to the internet for all 3 sites. There appears to be a problem with the AD at site 2, it is extremely slow to replicate. We plan to install a new DC & GC (2003) at site 2 and test. If still no luck, we will install 2007 at site 2 and migrate those users first. Any other suggestions? Thanks matey

Just to add, after reading something on MSExchange.org, the central Exch 2000 box at site1 has a smarthost configured on it's SMTP server properties, sending to a Mail Marshal server (and then out to ISP). This may be a clue (itmay try sending all mail, including for the Exh 2000 at site2) to this smarthost. We will disable this today and test. Thanks