we have recently upgraded our exchange from 2003 to 2007 , everything went smooth and all migration was perfect. but we are facing an issue which we cannot understand the reason for. the problem is that there are some domain we cannot recevie emails from also in some cases it is just specific sender from that domain e.g. which i am about to share with you all. our employee using gmail sends an email to his own email inside the organization, doesn't get recevied. If I myself send an email to my own email address inside the organization, get recevied.
Exchange 2007 SMTP recevie connector log shows that when the user send using gmail the connection was made from gmail server but when the session closes with "Remote" where as with my email the log closes with "service closing transmission channel" and "Local". apperantly my email is seen in the inbox where as his email does not reach his inbox at all.. disappeared in thin air.
logs are attached for reference
addtionally, if you look into the log you will observe that the message was recevied but it didn't got queued for delivery.
by the way we have two server , one HUB/CAS and second Mailbox