Calendar button missing - On Prem 2016 Exchange

Occasional Contributor


We have a on-prem 2016 exchange with the lastest updates, but we still doesn't get the Calendar button in teams.

Is this even possible when we only have an onpremise exchange and not hybrid? 

38 Replies

To me it looks like this should be working based on what MS says online, but its not. Maybe it's possible to start connecting the exchange and O365 without moving all the mailboxes into O365?

We haven't done anything with the "Hybrid" setting in our ECP.




With Exchange 2016 SP3 or later I should work, but you need to sync exchange properties with AADSync. Exchange EWS have to be published for your on-premises environment.
That means I have to start the Hybrid config in our ECP to make it work?

@has-dbk No, you just have to make sure that your exchange servers are published in a correct way so it is accessible from internet. And make sure that when you are synching users from Windows Active Directory to Azure Active Directory (with Azure AD Connect / DirSync) that you sync exchange properties.



@Linus Cansby Unsure what exactly your meaning then, we are currently syncing this. 



@has-dbk Enable "Exchange Hybrid Deployment" option in Azure AD Connect and re-run HCW (new version released yesterday - The key is OAuth configuration.


@Edson Serrano as far as I know, the Exchange Hybrid option in Azure AD Connect should be enough. Exchange Hybrid configuration is something different and not needed for the calendar functionality in Teams when the mailbox resides on-premises as far as OAuth Authentication between Exchange and Office 365 is working. 


Please correct me if I am wrong



I have the same problem/question and I'm new to exchange and O365 authentication methods.

Can you tell how I can check if OAuth is functioning after configuring Azure AD Sync and if not, what need I to do to get OAuth working?

Kind Regards



@Edson Serrano Thanks for your answer. We have now done the steps with configuring the hybrid environment, and moved a couple of mailboxes to the cloud, even then they wont get the calendar button.

If we move new mailboxes from on-premise to O365, they get the calendar button.


Could Oauth still be the problem?

Best Response confirmed by has-dbk (Occasional Contributor)


I had exactly the same issue as you and have solved it by following OAUTH manual setup to the letter via this doc


Get-IntraOrganizationConnector |fl Name,TargetAddressDomains,DiscoveryEndpoint,Enabled


brought no errors but no data.  I had previously ran HCW and this completed with no errors (I assumed the hybrid process was fully complete).  Exchange 2016 on premises, premium office 365 with licenses applied for exchange online plan.  No mailboxes have been migrated, all are on premises.  On premises existing Mail contacts and groups WERE visible in exchange online admin.  AD Azure connect was already run with optional hybrid exchange enabled.  Calendar button did not appear in teams. Teams worked otherwise.


So I ran the manual configuration of OAUTH from that link and calendar button started to appear after 30 mins.  Again, these are ALL on premises mailboxes, we have not migrated any mailboxes yet.


One caveat, at the end of the process you need to create an AD object - this object had already been created so it looked like HCW had at least tried to make the OAUTH link but hadnt fully completed it.





you must have an Oauth configuration for the calendar to appear. To do this either enable a Full Hybrid solution which will configure Oauth for you, or exchange minimal hybrid +


@David Bargna thanks! It's finally working after enabling Oauth :)


@David Bargna please allow me to add my 2 cents. 


You don't really need Exchange full or minimal to get the calendar button in Microsoft Teams. 

It is enough if you have

  1. Azure AD Connect, active Exchange Hybrid under sync options
  2. Autodiscover entry in Public DNS and Exchange Server accessible from MS Teams IP addresses
  3. OAUTH configured as described in the following article, steps 1-5 should be enough


Please let me know if your issue is solved and mark also the reply that helped you as correct. 


Thank you



@Spiros Karampinis 


I agree Spiros.  I am configuring this for my organization as well and have been looking into this.


For those interested explains what is required.  While the article writes OAuth must be configured "preferably via the Hybrid Configuration wizard" it doesn't say it is required.


I have this requirement too.  I don't want any Exchange online functionality and want to retain my on-premise Exchange for now.  Can I enable the Exchange hybrid deployment in Azure AD connect without worrying about breaking anything to do with my on-premise email?


I have hybrid enabled and have not migrated any mailboxes.  My onsite exchange still retains full functionality.  OATH was the critical configuration missing from my setup.




Enabling Exchange Hybrid in Azure AD Connect should not break anything.  However, please review this link for the list of attributes that could be edited on the on premises AD objects.


Also, please view this thread:


Hi there, can you clarify one thing on you caveat? Im not sure what you mean create an AD object? We've done all other steps, both with the hybrid and manual oath and still don't see calendar button. (ADsync also has exchange hybrid enabled). So frustrated with this.