Here are the few troubleshooting steps which will be helpful during messages stuck in local delivery queue

Open up the queue viewer and check for last error information in the local delivery queue

Open  the event viewer and look for event id 2080 and check for GC and DC availability

Increase  the Diagnostics logging for the following keys in the registry for Dsaccess

General

Cache

Topology

Config

Ldap

Restart the system attendant service and check  if we could find any relevant ids

Check  with the directory access tab on ESM   and see if DC and GC are listed

Finally you can go ahead and hard code the exchange server to listen on a particular DC if nothing works.

Note:Changes in registry should be made properly and correctly else it might make the exchange server not to listen to DC’s

Added the following registry keys.

 HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeADAccess\Profiles\Default\UserDC1

IsGC = REG_DWORD 0x0

Hostname = REG_SZ <DC Name>

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeADAccess\Profiles\Default\UserGC1

IsGC = REG_DWORD 0x1

Hostname = REG_SZ <DC Name>

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeADAccess\Instance0

ConfigDCHostName = REG_SZ <DC Name