Teams Native Chat Problem

Occasional Contributor



following szenario:


  • Tenant A user is Teams Only (Moved from SfB Online to Teams Only a year ago)
  • Tenant B user had S4B on prem (no usage) and was using Teams in parallel (No Hybrid). On Prem S4B user was removed, changes synced to cloud (lync attributes removed, sip address changed to UPN). User was upgraded to Teams Only 2 days ago. Tenant B users new sip domain (from UPN) has no external Skype for Business DNS records like

I would expect that the new Teams native chat should work here but following problem occurs:


Tenant B user sends chat message to tenant A user. Tenant A user receives the message but a Skype Symbol is displayed next to tenant B user. The Message "Due to an org policy changeyou can enjoy a richer chat and calling experience" is displayed. When clicking the link a new chat opens with rich features but the reply there is again received in a new chat on Tenant B users Teams. So replies to messages initiated in either tenant always end up in a seperate chat. 


Do we need to add the SIP DNS records despite native federation capability here to solve the problem or is this completely unrelated? What could be the problem here?

5 Replies

@Thomas Oeser So on Tenant B its a new Domain and no External DNS records has been setup yet? 


If no record has been created, please do so using the below overview: 



And make sure the following is configured: 

2020-03-27 13_58_54-External access - Microsoft Teams admin center.png


Also Teams upgrade, check this as well. 

The Coexistence mode that is used determines both routing of incoming calls and chats and the app that is used by the user to initiate chats and calls or to schedule meetings.

Put it on "Teams Only" when Skype is not being used anymore. 

2020-03-27 13_59_14-Teams upgrade - Microsoft Teams admin center.png



@Mitchell Bakker 


Thank you for your answer. Based on my understanding the global setting for Coexistence mode does not need to be touched. Should work on an individual bases. My assumption was that Teams native federated chat does no longer need the external DNS records and instead the chats are routed directly in the Office 365 Teams infrastructure. But i could be wrong on that.


So if the missing DNS records could be the problem here, i think i will give it a try.

If your org isn’t set teams only it might still be utilizing the dns records. I would just add them anyway. You def don’t need the org changed for federation(external chat)to work properly.

It could be a timing thing. Those changes to upgrade mode used to take up to a week. I figure they would have fixed that by now but with everything going on with system load lately they could have scaled back and it might be taking a bit longer.

Anyway try the dns and let us know!
Team drh

@Chris Webb 


thank you, it was indeed a delay after applying the teams only mode to the users. After about 48 hours everything works as expected now even without the DNS entries. But we will for sure ad them as well.