Hi all,

The next issue is bothering me for days now.. hope someone can point me to the solution :)

I've got an Exchange 2010 server (14.03.0146.000) with all roles installed (except Lync)   

I've got an application who uses an SMTP relay. 
I've set-up a recieve connector, to allow the IP adress of the application server, with anonymous access. 

I can send an e-mail to a user, or to distribution group A. But it doesen't work for distribution group B.

Offcouse I checked if the "require that all senders are authenticated" is not checked. Even with Get-DistributionGroup <<naam>> | fl  I can't find an diference between group A and B..

- The message doesn't stay in the queue
- Mails to Group A are in the message tracking, messages for Group B are not.
- I can send mails from Hotmail/Gmail to Group B
- No difference if I make it an Mail Universal Group or Mail Universal Security Group. 

Hope someone can point me in the right direction! 
Kind regards,