Aug 10 2017 08:46 AM
I have a tenant with 2 domains. Domain.com and Domain.co.uk. They have mail enabled public folders. The issue refers to all public folders but I am using sales@domain.com as an eample here.
When someone external sends and email to sales@domain.co.uk it is received in the sales public folder which has sales@domain.com associated with it even though sales@domain.co.uk is not listed as an email address is the public folder properties. Im not sure how this is working but this is in fact how we want it to work.
However is a staff member send an email from his @domain.com account to sales@domain.co.uk it returns the following error:
"Your message to sales@domain .co.uk <mailto:sales@domain.co.uk> couldn't be delivered.
sales wasn't found at domain.co.uk."
Can someone help me resolve issue?
Thanks
Aug 10 2017 09:18 AM
Aug 10 2017 11:01 AM
SolutionThat's a long standing issue with Public folders - their secondary addresses do not flow to the EOP backend, which has the Directory Based Edge Blocking feature. Well, actually a similar issue with O365 groups exists. In a nutshell, the DBEB feature blocks every message addressed to "unknown" recipient. For "regular" object types, it's not a problem. For PFs however, only the primary SMTP Address is synced, so only this alias is recognized by DBEB.
You have two options here:
1) Change the domain to Internal relay. This disables the DBEB feature, however might have other implications, so test before committing to it
2) Simply "cycle" the aliases - set the secondary one as Primary, wait for say 30 minutes, switch it again.
Now, my memory might be failing me, but I think I recall that the second solution only worked for Groups, sooo in your case I guess there's only one solution. I'll double-check...
Aug 10 2017 11:03 AM
Oh, in case those are on-prem PFs, check out the recently introduced AAD Connect PF sync feature:
Aug 11 2017 05:12 AM
Great explanation. Thanks for clearing that one up for me.