Mail Contact showing as UserMailbox in Exchange Online

Copper Contributor

In a Hybrid environment, mail contact is created in Exchange Onprem and it is syncing in Exchange Online as "User Mailbox"


The Proxy address settings are not getting synced, please advice what could be the issue?Showing as contact in OnpremShowing as contact in Onpremsyncing as mailbox in onlinesyncing as mailbox in online

7 Replies
Have you given the mail user and license in Office 365? That would explain the mailbox in Exchange Online
Hi Dan, Yes license is assigned to user, will try removing it and update here about the outcome

Hello, @Sivachandran_Palani 


welcome to the Microsoft community, my name is Recep I'll be happy to help you today.


If you are facing an issue where a mail contact created in Exchange On-Premises is syncing in Exchange Online as a "User Mailbox" instead of a mail contact, there are a few steps you can take to troubleshoot and resolve the problem. Here's a step-by-step guide:


Check the Recipient Type of the Object:


In Exchange Online PowerShell, run the following command to check the recipient type of the object:


Verify the Mail Contact in On-Premises Exchange:


In your on-premises Exchange environment, run the following command to verify that the mail contact is indeed created as a mail contact.


Check Sync Status:

Ensure that the Azure Active Directory (AAD) Connect sync is running successfully and has synchronized the changes from on-premises to the cloud. You can check the synchronization status using the AAD PowerShell module.


Force Synchronization:


You can force a synchronization from the AAD Connect server. Open a PowerShell prompt on the   server where AAD Connect is installed and run the following commands:


Examine Attributes

Check the attributes of the mail contact in both on-premises and online environments. Ensure that the necessary attributes such as RecipientType, RecipientTypeDetails, and RemoteRecipientType are set correctly.




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Hi Recep_Gencaslan695, Ran the script in on-prem and it didnt't give any results. Checked again in ECP and found it is not a Mail contact it is created as "Mail User". So if it's created as Mail user and licensed added will it sync as mailbox to exchange online? If Yes why the changes in primary SMTP are not getting changed in online? Any steps to check on this further?
It sounds like an issue with the AAD connect sync for this object, you'll need to check the logs to see why. Is this an admin account at all?
Hi Dan, No this is not an admin account, it is created as Mail user and not getting synced properly, can you provide steps where should I export and check logs to find if this is a sync issue else you can give me link of any KB's I can try and find a way to do that. Thankyou
The AAD Connect Synchronization Service Manager installed on the same server as AAD connect will show you some details. Here are some steps to troubleshoot