Queue Problems - 451 4.4.0 DNS Querry Error

Question

Our Current set up:
Server1: Hubtransport, Mailbox Server
Server2: CAS, Hubtransport server
Server3: Exchange 2k3 mailbox server
   Our issue is we are unable to send email to a specific domain. It doesn't matter if the person sending the mail is on the 2k7 or 2k3 mailbox server. The queue's last error states: "451 4.4.0 DNS query Failed."
I can however do a NSlookup from the machine, and telnet to their mailservers on port 25 and get a helo response.
I have enabled send connector protocol logging and nothing even shows up in the log about trying to contact this domain.
I am at a loss as to where to look next. How does exchange 2007 handle its DNS resolution. Please help.
Thanks
Here is the results of Get-Sendconnectors |FL
AddressSpaces                : {smtp:*;1}
AuthenticationCredential     :
Comment                      :
ConnectedDomains             : {}
ConnectionInactivityTimeOut  : 00:10:00
DNSRoutingEnabled            : True
DomainSecureEnabled          : False
Enabled                      : True
ForceHELO                    : False
Fqdn                         : dls.rutgers.edu
HomeMTA                      : Microsoft MTA
HomeMtaServerId              : Server1
Identity                     : DLSExch07mail
IgnoreSTARTTLS               : False
IsScopedConnector            : False
IsSmtpConnector              : True
LinkedReceiveConnector       :
MaxMessageSize               : 10MB
Name                         : DLSExch07mail
Port                         : 25
ProtocolLoggingLevel         : Verbose
RequireTLS                   : False
SmartHostAuthMechanism       : None
SmartHosts                   : {}
SmartHostsString             :
SourceIPAddress              : 0.0.0.0
SourceRoutingGroup           : Exchange Routing Group (DWBGZMFD01QNBJR)
SourceTransportServers       : {Server1, Server2}
UseExternalDNSServersEnabled : False
From the Logs in:
C:\Program Files\Microsoft\Exchange Server\TransportRoles\Logs\Connectivity
2007-08-23T14:29:03.954Z,08C9B3176617F11F,SMTP,sabert.com,>,DNS server returned ErrorRetry reported by 0.0.0.0
2007-08-23T14:29:03.954Z,08C9B3176617F11F,SMTP,sabert.com,-,The DNS query for 'DnsConnectorDelivery':'sabert.com':'247c4dcf-5bc9-4621-b64d-aa43ed43bf55' failed with error: ErrorRetry

Answer 1

>Had one external DNS on the NIC along with our PDC and backup DC. Went ahead and removed it.
That's not a good thing. Did you also flush the DNS cache with
"ipconfig /flushdns" and restart the DNS Client service?
>As for the "get-sendconnector" it believes it is going to {SMTP:*;1}.
Maybe, but it shouldn't be going to ANY send connector. You have just
one Exchange server and the e-mail is purportedly addressed to a domain
in your accepted domains.
So, is 61027a30-e9a9-4c2d-acb5-c1efc96d5d8b your send connector, or
one of your send connectors?
Let's see the output of this:
get-sendconnector | fl *
And this:
get-accepteddomain | fl
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP
Flushed and registered DNS and restarted DNS client.
Removed Send Connector to try mail without it but no luck, still goes to queue with same error.
I wasn't sure what NextHopConnector 61027a30-e9a9-4c2d-acb5-c1efc96d5d8b was so I ran get-sendconnector <guid> and it came back with:
The operation couldn't be performed because object '61027a30-e9a9-4c2d-acb5-c1efc96d5d8b' couldn't be found on '<backup domain controller>.local'.
    + CategoryInfo          : NotSpecified: (:) [Get-SendConnector], ManagementObjectNotFoundException
    + FullyQualifiedErrorId : F31958E9,Microsoft.Exchange.Management.SystemConfigurationTasks.GetSendConnector
So, it appears that the NextHopConnector is not being located in the AD (which I don't even know why it's looking at backup DC instead of primary) like it should.  When I run get-sendconnector | fl * I get:
get-sendconnector | fl *
PSComputerName               : <Exchange FQDN name>
RunspaceId                   : 2faaf0ee-9a3d-4542-b69f-9fc9548242fd
DNSRoutingEnabled            : False
TlsDomain                    :
TlsAuthLevel                 :
ErrorPolicies                : Default
SmartHosts                   : {<ISP SMTP relay>}
Port                         : 25
LinkedReceiveConnector       :
ConnectionInactivityTimeOut  : 00:10:00
ForceHELO                    : False
IgnoreSTARTTLS               : False
Fqdn                         :
RequireTLS                   : False
RequireOorg                  : False
Enabled                      : True
ProtocolLoggingLevel         : None
SmartHostAuthMechanism       : None
AuthenticationCredential     :
UseExternalDNSServersEnabled : True
DomainSecureEnabled          : False
SourceIPAddress              : 0.0.0.0
SmtpMaxMessagesPerConnection : 20
SmartHostsString             : <ISP SMTP relay>
AddressSpaces                : {SMTP:*;1}
ConnectedDomains             : {}
IsScopedConnector            : False
IsSmtpConnector              : True
Comment                      :
SourceRoutingGroup           : Exchange Routing Group (DWBGZMFD01QNBJR)
SourceTransportServers       : {<Exchange DNS name>}
HomeMTA                      : Microsoft MTA
HomeMtaServerId              : <Exchange DNS name>
MaxMessageSize               : 10 MB (10,485,760 bytes)
AdminDisplayName             :
ExchangeVersion              : 0.1 (8.0.535.0)
Name                         : <company>
DistinguishedName            : CN=<company>,CN=Connections,CN=Exchange Routing Group (DWBGZMFD01QNBJR),CN=Routing Groups,CN
                               =Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=<company>
Excha
                               nge Server,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=<domain>,DC=local
Identity                     : <company>
Guid                         : 09833378-b5c5-4581-9622-aa358087caf8
ObjectCategory               : <domain>/Configuration/Schema/ms-Exch-Routing-SMTP-Connector
ObjectClass                  : {top, msExchConnector, mailGateway, msExchRoutingSMTPConnector}
WhenChanged                  : 11/2/2010 9:35:14 AM
WhenCreated                  : 11/2/2010 9:35:14 AM
WhenChangedUTC               : 11/2/2010 2:35:14 PM
WhenCreatedUTC               : 11/2/2010 2:35:14 PM
OrganizationId               :
OriginatingServer            : <backup DC>.local
IsValid                      : True
get-sendconnector 09833378-b5c5-4581-9622-aa358087caf8
Identity                               AddressSpaces                     
Enabled
<company>                        {SMTP:*;1}                          
True
So..is there a way to change this NextHopConnector pointer record so that mail enters the queue with the correct guid?
Thanks