"We can't set up the conversation because your organizations are not set up to talk to each other"

Frequent Contributor



I'd like to know if I'm interpreting the following message in Teams correctly when I try to start a chat with a user that is not in our tenant.


"We can't set up the conversation because your organizations are not set up to talk to each other."




Does this message only appear for those external users which also use Office 365 / Teams?

I'm thinking that's the case since there're other external users, for example from "" that which I can add as a guest user.


If that's the case would it mean that in order to chat with users where this message is presented external access scoped to their domain has to be enabled in the Teams admin center? Would only we have to toggle that switch and add the external domain or the other company as well?


Thanks for your input.

19 Replies
Hi Florian,

If you have external access turned on in your tenant and have invited others before without issue it sounds like the other organisation, which may have Office 365 does not have external access turned on. Have you confirmed those things with the user?

Best, Chris

Check if you activated the External Access in Teams Admin Portal.


Do you know if your partner uses Teams or Skype for Business? Skype consumer is not supported in federated chat from Teams.

Yes federation needs to be enabled for both! You don’t specifically have to add their domain if you want to allow all!

No, we've never had external access turned on before. I'm actually just figuring out the difference between guest access and external access. For this, I wanted to start a chat with a test user that only has an "" email address outside of our tenant.


When starting a chat I notice two different options.




The first one works to start the chat (as we have guest access turned on) but the second one doesn't, giving the aforementioned error message.


Does the first option correspond to the admin center setting: org-wide settings -> guest access

and the second one to org-wide settings -> external access?


It's quite confusing at the moment.

Hi @Florian Hein,

Sure. Understood.

Yes - it would be good to hear @adam deltinger and @Linus Cansby opinions here too but from what I understand (and to note I may very well be wrong here) that the second one is to search for that user within the Azure AD Environment so its for users who are using Teams within an office 365 tenant.

Guests who are in other 365/Azure AD environments are different from Guests who are not in those environments and only use something like GMail, Hotmail, etc.

Hope that helps to clarify.

Best, Chris

Best, Chris
Doing federation with an hotmail, gmail etc can’t be done? Only if those accounts have been invited as a guest in your tenant! They are then users in your azure active directory!
Federation only works to other teams users in other office 365 tenants and also s4b to some extent!
For this “external chat” to work they need an office 365 account and a teams/s4b license!
Commercial Skype won’t work either and as it seems not for a long time or ever!

Guest: invite any address to your tenant through a team or in azure AD and collaborate within a team where the guest user is a member!
Guests can access your teams sharepoint files within the team and access channel conversations and other content!

Federation: just external chat ( think S4b) you can share files also through chat but files end up in the sharing users onedrive!

I hope this clarifies?


Haha glad I was right in this case! :D

But Microsoft need some better documentation round this - guests is probably the biggest issue in the Tech Community in terms of confusion. May be better of in splitting the names like Federated Guests and Non-AzureAD Guests or something like that.

Best, Chris

I agree, the second one that says "Search <user> externally" will go out a create a federated chat. That requires that External Access is enabled. You can enable external access to Teams only or to Teams and Skype. If you start a chat with that user (if you find it) the chat will end up in their Skype or Teams client.



The first contact with (Guest) is an invited to your tenant. If you send a chat message to that contact they will receive it in your tenant so if they want to read it they have to switch tenant in Teams (if they have their own Teams tenant). This type of user can be a member of a team and read documents, chat, etc. You activate this in Guest access.


Another thing to think of when chatting with Guest accounts is that chat can be disabled for guests  from the Teams & Skype Admin Portal in the the Guest Access section.



Think of it like this:
calling a friend and talk to him/her about a project doesnt make the person your guest!!
If you invite your friend over to your house to work on a project , that person now is a guest at your place right?


Yes, spot on analysis.

I’ll add this to the AMA list then guys. Add got my list down by one yesterday by spotting custom requests in Shifts but this has just replaced that.

Best, Chris
You know I am going to quote you in the AMA with that 😂

@Christopher Hoard won't be answering many questions in the AMA next time, you'll be busy with your mega list lol....


@adam deltinger and @Linus Cansby are on point with the differences. 


  • Guest chat, pretty much is a chat that happens in the tenant it originates in (so guest recipient has to switch to your tenant to chat inside their Teams client, can be free or paid Teams). 
  • Federated chat is a remote tenant to tenant chat that takes place from each participants home tenant client (Teams or S4B dependent on upgrade modes). 
  • No Federation between Teams to free Teams users, or consumer Skype. Only exception here is Skype for Business to Skype Consumer 




Thanks a lot everyone for the detailed answers. This helped my differentiate better between the two.


@Chris Webb, when you say "guest recipient has to switch to your tenant to chat inside their Teams client", how does that look like? Is this a prompt that the guest user will see in his Teams desktop/web client or is it seamless?

This is how it looks, next to my profile picture I have a drop down list where I can select two other tenants where I'm a guest. When I select one of the other tenants my Teams client will sign out from my UClarity tenant and sign in to the other tenant where I am a guest.


And when you’ve switched tenant, you use chat as usual via the chat button on the left! But you are now chatting within their tenant with an internal guest account
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