Wednesday, November 03, 2010

Mail Enabled Groups In Exchange 2007 Not Working From Outside Senders

We recently ran in to this problem, and it took us a bit of time to track down.

We created a mail enabled group in exchange 2007, which worked great internally, but would reject messages sent from external senders with a "550 5.1.1 User unknown" error.

The fix? go to the group properties, "mail flow settings" tab, "message delivery restrictions"

un-check the box "require that all senders are authenticated"

Really, it should be obvious, but it took us a while to figure out, and certainly any exchange admin should know it...

1 comment:

Alexis said...

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