Hi Aleds,
You mean all the members of distribution group have not received the email, right?
How did you add the distribution group on the Exchange Server 2010?
If add the group as mail-enabled group on Exchange 2010, you don’t need to use transport rule.
On the Exchange side, you can follow these steps to have a try:
<1> You can create an account in the AD (let’s say Test) and configure your outgoing mail with this account.
<2> Create a Universal-Security group in AD (let’s say Test Group)and added members to this group.
<3> Since this is Universal-security Group, you can add it as Mail Universal Security Group on Exchange 2010:
Exchange Management Console->Recipient Configuration->Distribution Group->New Distribution Group->choose Existing Group->choose
“Test Group”->Next->input the alias for the group(I keep it the same as group created in AD)->Next->New
After that when
you use account (Test) send emails to Group (Test Group), all the members in Test Group will receive the email.
Thanks,
Evan