This articles applies to:
Office 365
Exchange hybrid
PROBLEM:
After a mailbox is moved to Office 365 the user does not receive messages sent to an on-premise dynamic distribution group any more.
CAUSE:
Dynamic distribution groups are built on a query. By default, this query is set to search for mailbox users. When a user mailbox is moved from the on premise to Office 365 Exchange online, his mailbox type changes to mail user. Due to that, it does not get picked up by the query anymore and “falls off the list”.
SOLUTION:
In your on-premise Exchange Admin Center, go to Recpients / Groups and select the group you want to correct.
In the Distribution list properties, make sure that the option Mail users with external email addresses is selected. This will insure that the mailboxes located in Office 365 Exchange Online will be included as well.
If you created a dynamic distribution group using a custom PowerShell script, you will not be able to edit it via Exchange Admin center GUI.
Modify your query syntax to include Recipients of Type MailUser (see example below)
Default Query
((((Department -eq ‘Finance’) -and (((RecipientType -eq ‘UserMailbox’))))) -and (-not(Name -like ‘SystemMailbox{*’)) -and (-not(Name -like ‘CAS_{*’)) -and (-not(RecipientTypeDetailsValue -eq ‘MailboxPlan’)) -and (-not(RecipientTypeDetailsValue -eq ‘DiscoveryMailbox’)) -and (-not(RecipientTypeDetailsValue -eq ‘PublicFolderMailbox’)) -and (-not(RecipientTypeDetailsValue -eq ‘ArbitrationMailbox’)) -and (-not(RecipientTypeDetailsValue -eq ‘AuditLogMailbox’)))
Modified Query to include also Office 365 mailboxes
((((Department -eq ‘Finance’) -and (((RecipientType -eq ‘UserMailbox’) -or (RecipientType -eq ‘MailUser’))))) -and (-not(Name -like ‘SystemMailbox{*’)) -and (-not(Name -like ‘CAS_{*’)) -and (-not(RecipientTypeDetailsValue -eq ‘MailboxPlan’)) -and (-not(RecipientTypeDetailsValue -eq ‘DiscoveryMailbox’)) -and (-not(RecipientTypeDetailsValue -eq ‘PublicFolderMailbox’)) -and (-not(RecipientTypeDetailsValue -eq ‘ArbitrationMailbox’)) -and (-not(RecipientTypeDetailsValue -eq ‘AuditLogMailbox’)))
