Communicate with an external Skype for Business user

Harrison Hersch

In MS Teams, how do I communicate with a Skype for Business user not in my directory? Someone in another company? In Skype for Business, we just input their email address. Doing that in Teams under people, doesn't seem to ever result in anyone. I've already turned on globally the guest access feature of Teams.

58 Replies
You cannot do this yet, it's Skype federation and it's on the roadmap. I think the federated chat by end of this quarter is that item but not sure. I know it's being worked on and you cannot do it yet. https://skypeandteams.blob.core.windows.net/artefacts/Skype%20for%20Business%20to%20Teams%20Capabili...
Now if they have Teams instead of Skype for Business in that other organization you can invite them as guest to your Team and then they can Chat/Team Chat with you on your instance.
How can you invited them as a guest user if they don't have an O365 license? This is baffling to me how we can use Teams and Skype to replace our web conferencing system.
You can't yet, they are working on it. It's coming, it takes time to develop.

Is this fixed yet? We can't seem to invite external users

Are you talking about external SfB users or just external users for Teams? You can invite external users in Teams. But you have to enable it in a few places. First you need to enable external users support in Teams (Office/Microsoft 365 admin center > Settings > Services & add-ins > Microsoft Teams: Settings by user/license type - change to Guest and change it to On and Save). This will enable new Teams (old one won't be affected) to be able to invite existing external users. If you want to invite completely new external users, you can first add them manually in Azure admin center or you can enable Office/Microsoft 365 admin center > Settings > Security & privacy > Let users add new guests to the organization. Also note, that after changing these settings, you might need to wait 1-24 hours for them to take effect (yeah, that's how modern cloud services operate..).

Btw, those external users must have a Microsoft ID (could be personal one).

Thank you. We are guest enabled already.

Currently through SFB, we communicate outside of our org with other SFB Users.

If we go to Teams soonish, we'd want to be able to still communicate with those SFB external users. Is that working in Teams yet?

Teams to Team yes as long as both Tenants have latest build, don't think it's 100% just yet thou. Not sure if it works from one tenant Teams to another Skype for Business. If you are Skype for business and want to send me your Sip ID I can try it from my Teams.
FYI for others curious, the Test worked from my Teams chat to his Skype for Business endpoint.

How did you do it? Did you just type his SfB id on the TO: filed of the chat window?

I'm trying this and I get  "we could't find this person. Try another e-mail address.

You and or they don't have the presence update most likely. I don't think it's 100% pushed yet. If you want to message me your primary e-mail / sip address I'll test with you as well since I have the updates. If it doens't work you don't have them, if it does they most likley don't, and or they don't have the option to communicate with external folks turned on in the new admin center.

Thanks, I'll get back to you tomorrow.

Any update on this?? I've got external federation enabled.. Have dozens of external contacts in S4B, however cannot find them in Teams.  This is very cumbersome and is in no way a Skype replacement right now.  I'm even on the Developer preview!!

Hi, any update on this ?

Seems we are still not yet able to add external users (through Skype federation) in the chat of Teams

You can enable external communications, which in turn will allow you to chat with people on external Skype for Business and Teams. However, it's not always that simple to keep track off and some people don't get it to work at all. 

For now, my tests have been fine.




Was there any update to this at Ignite? OR is it the case that MSFT is trying to push everyone onto Teams ASAP and therefore there is no need for this functionality? It seems the MSFT answer is to invite the external user to a Team, and then do chat 1:1 or in a channel in Teams?

This is how it works for me:

Contact an external Skype for Business user from within Teams without giving Guest Access.

Click the ‘New chat’ icon. 1.png


Type in the SIP address of the person to contact



Click ‘Search sip@address.com externally’.



Type your message and send.



To contact the person faster in the future, go to Chat > Recent, right click the person and ‘Add to favorite contacts’.



 Thats the only option I see.. Do I need to do something special ?





Make sure your tenancy has external contact search turned on. It can be found in the Skype & Teams Admin centre. It can take a couple of days for the function to become after activating. 


I've just tested using Daniel's description and I can see external users.  Still need to fully test the functionality that I can perform with them so the jury is still out. 

Not sure if this helps here, but I attended a session at Ignite that outlined the current status of Teams and Skype federation:




Seems to indicate that your geo will dictate the availability/current status of federation.




Hi Keith,


It works in my private Office 365 tenant, now we want to enable this in our corporate tenant, but we can't find the option in both tenants.


Could you maybe make a screenshot of the location of the setting within the Skype and Teams Admin Center.





Here is a screen-shot of the setting in the Teams/Skype admin centre

Aaah Cheers James, we were lookup for a setting called "external contact search" ;)

Thanks for the great tips guys. 


I keep getting this message when I try to connect to an external SFB SIP account. We have confirmed that the external organization has enabled the "external" connection access on their side as well. 




Am I missing something?




I have the exact same situation. So, I opened a support incident at O365. But after 2 hours checking my config and the config of the other Tenant - it seems they have no Idea why. We figured out that one single contact from the other Tenant we are able to chat,  see his presence, do phonecalls over federated sip. Strange Thing: That user has the same config as other users from the same tenant, where we cannot communicate with.


Just as an update - The other organization was (and still is) on SFB and haven't yet moved to MST. Guess SFB-MST don't like to talk to each other? 


In any case, I've ended up having to create an Inter-corporate group/channel and push all external users as guests. Not ideal by any count; but it gets the job done. For now.



I'm having the same issue here.  I created a new O365 tenant last week.  Everything works great with IM to external users in S4B, but not in teams.  In teams I search for people and some days I get the message about our orgs not being connected, and some days it just says no results.  I opened a support ticket with O365 support and they said the other domain has to whitelist my domain, which seems incorrect according to the documentation.  As long as I have external access enabled in the teams admin center, and no domains listed, all domains should work.  I'm trying to IM @microsoft.com users.  I'm a former employee and want o chat with my former colleagues through teams :)  

Hi Oleg, 


I am trying to enable the option for our organization but unable to do so. 

I was trying to enable it via Services & add-ins > Microsoft Teams: Settings by user/license type - change to Guest and change it to On. But the Option ON is grayed out. 

Any idea what might be the issue?

This setting is moved to the Skype and teams admin center!
You reach this from the admin portal as well!



Kaushalya, you are referring to an old setting which was to enable guest access to Teams itself. But this topic is about communicating with external Skype for Business users via Teams. So i'm not sure what you want to achieve. As Adam mentioned the setting you refer to has been moved to Teams & Skype admin center. One can also enable communication with external Skype users in the same admin center. Read through the topic and check the screenshots.

I think he replied to your post a while ago we’re you described how to add guests to teams..
The old settings location was described there as well :)


Hi Adam, 


Thanks for the reply. In that case, the page shows can't upload any data. Any advise? 




Hmm! Try using a different browser!
This setting is for federation to other tenants! Might also be what you want but the settings for teams guests is under “guest access”

Hi Adam, 


Same issue in all browsers and a blank page opens while trying to open GUESS ACCESS option. Let me again go through it all again and check what am I doing wrong and let you guys know!

I think you are then better contacting Office 365 support.
Any News on this? We have the same issue?
Hey Daniel, if you don't mind going and starting a new conversation with your issue so we can try to help figure it out so we don't take this thread into multiple directions. Thanks!

Hi Oleg, 


I have the same issue up until now so yeah guess I will need to contact O365 support. 

Hi Daniel, 


Guess we need to contact O365 support like how Oleg has advised. Have the same issue up until now when checked via all browsers


any Updates and Solutions available? We have a new Office 365 Tenant (January´19) and we can not Chat with external SfB Users.

External Access is enabled, Domain Whitelist is empty, TeamsUpgradePolicy is set to "TeamsOnly".


What I see is that in the Chat window I don´t have the Contact-Groups (Recent / Contacts) shown in the left top ot the Microsoft Teams Client. I have seen other MS Teams Clients from another Office 365 Tenant where those Contact-Groups are shown. Don´t know it this is a indicator for a missing Tenant-Update ot Tenant-Setting


I realized with Chromium Version 70.0.3538.102 it is not possible to open the "admin.teams.microsoft.com" page. With Chrom Version 71.0.3578.98 and latest Edge it was no problem at all. I hope this helps and we can concentrate to the external Issue.

That’s odd. Are you on a gov cloud tenant by chance?

Hi Chris,

no, that is not the Problem. It is a "normal" Office 365 Tenant (Corporate).

It works on my Teams client.

Just click on "new chat" tab and put the email address of the external user.

As the user is outside your organization. Some Teams features won't be available (content sharing for example) but chat, audio & video are OK.

Note that my Teams client is configured as a Tems only user


Hope it helps



With Microsoft Support we figured out, that we had a missconfiguration on our external-DNS-Settings.

On hybrid Scenarios you have to keep ALL of your Skype for Business Server 2015 DNS-Entries to pointed to on premise. Our mistake was, that we point the lyncdiscover Entry to webdir.online.lync.com instead of the correct on Premise Reverse Proxy of the Pool-Server. After changeing this we was able to chat or do phone calls to external contacts via Teams. The only problem is that the communication will always endup on the federated company in Skype! Within this cross communication some features like sharing your desktop will not work. For this you need a Teams to Teams communication, like you have already with internal Users. And today the only workaround (which I know) is to invite your external contact to your Azure AD as a Guest-User. As soon the invited contact will follow the link and login with his own credentials to the invitatory O365-Tenant, this external contact will be treated like an internal user. In other words, we have a Teams-to-Teams communication, which is fully featured (sharing desktop included). Hopefully one day Microsoft will Teams allow to communicate with external users directly to Teams without hassling Guest-Status.

@zrhoul: This is the same way I am doing. As you can see in my screenshot it is not working. My Tenant Policy (TeamsUpgradePolicy) is set to "TeamsOnly" and my client too.


My Chat Conversation starts in my MS-Teams-Client and I want to reach a external Skype for Business Online chat partner. This is only working when I change my Tenant Policy (TeamsUpgradePolicy) to "Islands" mode. Then my chat conversation is working, but not over the Teams-Client. On both sides the chat message appears in the SfB-Client and the conversation is not going over the MS-Teams-Client.


I can not believe that this is the solution. Also I can not believe that I have to create a Guest-Account in my O365 Tenant for every external Partner (that is crazy).

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