Email Delays after moving users to Exchange 2010

[drlchua]

We are currently running BES 5.0.2 and recently upgraded to Microsoft Exchange 2010 SP1 from Exchange 2003. For testing, we moved 5-10 users were moved with no problem, users were able to send/receive from their bb devices fine.

When we moved all our users over the weekend, we started getting 5-30mins delays before users can receive emails on their blackberries. if we move a user to a static box then mail flow seems normal.

Fixes we've tried:

1) checked Send As permissions for BESAdmin account
2) added MaxSessionsPerUser = 100000
3) Set all RCA Parameters to $null

is there anything we missed to fully migrate to Exchange 2010 and not have these email delay issues?

thanks in advance for your help.

[titanjhb]

Might not be the answer, but where is your Exchange located in relation to your BES? Exchange notifies BES about new messages with UDP data packets, if the UDP packets go lost BES will start polling, every 15 to 30 minutes (they way I understand it anyway)