mail stuck in edge transport queue

I have a bunch of emails stuck in the edgesync - corp to internet queue and they have been there since friday.

These need to go out before they go NDR, but I can't seem to budge them.

both the hub server and the edge server have connectivity to the interent and I can ping and nslookup -q=mx on the targeted domains with out fail on both machines.

I see no errors in the event logs.

I get zero output at all (zip, nada, nothing) in the SMTPSEND log area.  I believe I have that turned on just fine.  I've even turned on the IntraOrgConnectionProtocolLoggingLevel to verbose.

I get a connection log and it has some entries that I can't decipher, much less act upon.
"Non-existent domain reported by x.x.x.x" (th ip was correct and it does respond to queries)"
and
"The DNS query for 'SmtpRelayWithinAdSiteToEdge':'edgesync - corp to internet':'<guid looking thing>' failed with error : InfoDomainNonexistent"

The Queue's Last Error column says "451 4.4.0 DNS query failed.  The error was SMTPSEND.DNS.NonExistentDomain; nonexistent domain"

First off, what address was it trying to resolve?  I've looked at the emails one at a time, and tested connectivity to the recipient and it all tests good.

Anybody got any ideas?  I've been struggling with this for hours now since I discovered the problem.

-g