Getting Started - Creating a team accross two tenants


Hi all,

I m new to Teams and looking to deploy it in our organisation. We have 10 in our office on DomainA/TenantA and 10 in another office on DomainB/TenantB (for regulatory reasons). We would like to set up a common team to chat, and have a few questions:


  1. As I understand, OfficeA can be the 'host' and invite those users from OfficeB into our team (Let your Teams users chat and communicate with users in another Teams organization). Has anyone tried this?
  2. I created a new team as a test, but it has ended up creating a new group, email address, etc. associated with that team. What is the purpose of this? I have not used O365 groups so am not familiar how this ties in with the rest of the ecosystem.
  3. After staff leave, we typically convert their mailboxes to shared mailboxes. They are hidden from the global address books, but for some reason they show up on Microsoft Teams. Is there any way to prevent this? We need to keep the user accounts active in order to maintain the shared mailboxes, but would prefer not to have all these names appear in the user list for teams.

Apologies for lumping a few into one, but very much appreciate anyone who can help.





40 Replies
Hi Ben,

1. Yes you can invite the other tenants users as guests - see

Having guest users is a common scenario and many of us here on the TC have several tenants we work in!

2. Here is how to add a Team to an existing Office 365 group

If you create a team and don’t link it to an office 365 group it’ll create an office 365 group,

3. Refer to this article about users leaving the business

Hope that helps and that I answered your questions. If I did please like and set as the solution. If not let me know what more you need. Hope to answer more of your questions soon!

Best, Chris

1: Yes you can either just use the chat feature to have communication between the tenants, share files via OneDrive etc..To invite users between tenants you invite them as guests in your team. They will now be able to have access to all resources like channel conversations , team files ,tab etc..


See here for more information:


2: This is by design! There is always an underlaying Office 365 group that get created when creating a Team. This is used for membership , files via SharePoint ( A teamsite gets created with a 365 group as well) etc.. Please read here about Office 365 groups and Teams:


3: Teams should honor any GAL policys: See here





Didn't see you there :)

No worries Adam! Same here! ✅

Thanks guys, appreciate the quick replies! Will have a look through those articles.


When it comes to former staff, there are 4 currently showing on my "Suggested Contacts". These are all shared mailboxes, and for all I have selected "hide from address lists" on the Exchange admin center, but they still show. Any ideas?


Rather than guest access, I was looking to invite those in our other office to join our team, using their existing Office 365 E3 accounts, if that makes sense?


Another question: is there any way I can disable SharePoint / OneDrive when it comes to Teams? We use Box exclusively and don't want to end up with multiple concurrent file repositories. I have added Box to Teams but haven't been able to find any way of disabling SP/OD.





"Rather than guest access, I was looking to invite those in our other office to join our team, using their existing Office 365 E3 accounts, if that makes sense?"


- This is the guest function :)


"is there any way I can disable SharePoint / OneDrive when it comes to Teams?"


disable SharePoint / OD licenses for users in the admin portal ->users ,  or use powershell



With the suggested contacts if this is in Outlook these will cache if you have emailed them previously. You can begin typing them again and when autocompletes delete them. If they still show in the GAL it can take up to 24 hours to come off. So I would check tomorrow, you can always redownload the address book in Outlook which may help.

Best, Chris

Thank you Chris! I missed this have to delete the autocomplete records right? These don't have anything to do with the GAL itself

if it's in GAL: Also turn off cached mode  - open close and open outlook then turn on cached mode if you use it - or just download the GAL again

As @Christopher Hoard said, it can take som time updating this automatically

They are talking about the type ahead in Teams not Outlook :P. For Teams it's basically cache, you have to wait awhile for it to clear out. Check web version / mobile and see if it's still there. If so might have to sign out and in on the desktop client, and or even go a step further and delete the cache manually to force the clear out. But always start with web client.
Thanks! I’ll make an implicit assumption it is Teams next time someone mentions suggested contacts in the context of mailboxes 😂 ✅

Thanks Adam. Sorry for the delayed reply, trying to sort this out while travelling.


I had followed the instructions here to connect the two tenants, which I believe is different to guest access:


Both tenants now have external access enabled and each has the other domain as 'allowed'. However when I run Teams and go to 'add members' I can still only add users in my own organisation.


Any thoughts?



Thanks Chris. Tried deleting from Outlook cache but the addresses still show up on teams. One of the users left in April, so haven't emailed them since then, and took them off GAL after converting to a shared mailbox. This isn't a big problem, but would be nice to remove them if I can find a way.

Read the page again, and it says it does require guest access to be enabled, my bad. Will see if this helps and will report back soon.


In the Teams and Skype admin centre make sure that external communications and guest access are enabled.

Let us know how it goes.

Best, Chris
You seem to have mixed up federation and guest access! Sorry if I’m wrong but I’m given mixed signals here :)
The link you pasted is federation - when you communicate between different tenants! We mean good ol chat here ( think S4b)! - this has nothing to do with collaboration within a certain team! This is the chat button on the left panel in the teams client..
For this to work you need to enable external access on both sides and the allowed/blocked domains if necessary!

You are also saying you want to “add members”! It sounds like you want to add external people to you team? (Guests)
In this case the guest options mentioned in this thread need to be enabled as well!


Thanks Adam. Get what you mean. What I am trying to do is get OfficeB onto the team for OfficeA, so we can communicate in the same channels (and chat).


External access, allowed domain and guest access are all on.


Even though I've enabled all the relevant settings, I go to "Add member" type in the user's email address, but I get "we couldn't find any matches". Any ideas on how I can get this working? Perhaps I need to wait a little longer since I've just enabled a few hours ago?

It could be propagation but how about logging out of Teams and all apps and closing them then logging back in? That may resolve it.

Best, Chris
Ok! Then we agree this is guest access :)
As @Chris Hoard said, if you set something to ON, there is some time to wait!
Just make sure that both teams and group guest access is set to ON!

And of course! Merry Christmas!!


Thanks, Merry Christmas!


I found this setting (see screenshot) which might be impacting the ability to add guests, but the option to toggle it is disabled. Any ideas?

Yes! This is the old setting in the office 365 portal that is now moved to the teams and Skype admin portal - under: I belive it says “guests”
The group’s guest setting is in the admin portal under services and addins - groups

You have to also make sure you have guest access for groups on as well. In the office admin center > services and addins > office 365 groups > couple setting there. But it takes up to a day for all these settings to take hold of you just turned on guest access you have to wait.

Hi guys,

It seems that Teams requires you to have the person as a contact (i.e. have initiated a chat) before you can add them to a team. I have tried to initiate a chat with a test user in our other office, and I get the error: "This user is unavailable or offline. We've sent an email instead." Screenshot attached.

They have teams installed and external access enabled. What would you suggest?

You do not have to chat. Chat federation and a guest of a team are two separate things.

In your screenshots that is federation. And the most likely cause if your issues is the end user you are trying to federate with is not in Teams only mode and either a. Does not have external Skype for business federation configured or b. Has Skype for business onprem and not configured for hybrid (not homed in s4bo).

So basically. The other end has to be Teams only for that user or the federation rules then turn to Skype for business configuration
And another thing they could be not set to Teams Only and just not signed into Skype for business at the time you tried to send it. Because Skype for business is not persistent you cannot send messages unless they are connected / online.

Thanks Matt. The user was signed in to Teams at the time. I was in our other office last week and was sitting next to them. But I will also ask the other admin to check that they have set the mode to "Teams only".


When I went to that setting in "Teams upgrade" in our Teams admin panel, it says this has been set by Microsoft. How do I know if it has been set correctly?


I've also enabled "Users can communicate with external Skype users" just now as well, in the hope this will help.


Appreciate the ongoing help.

Just to add, I see from the Teams dashboard the following:

Your Teams upgrade is complete
All the Skype for Business users in your organization have been successfully upgraded to Teams, as of Nov 30, 2018. Check out ​our tools and training resources to help your users get started with Teams.​


So I think this is why I can't set the mode.

Your side is probably fine, it's the receiving end that needs to be updated, otherwise it goes to Skype clients.

Perhaps it would be useful here to explain the difference between guests and federation.


Federation allows your users to start a text, voice or video call with people in a different organisation. It relies on those setting for you to trust the other organisation or more typically people leave it open to allow messaging to any organisation. At the moment it would only allow a 1:1 chat with simple text, not the full Team functionality. I don't think this is what you are really asking for.


Guests is where you invite someone from another organisation to access one or multiple Teams in your tenant. They can use nearly the full functionality of Teams, when they switch to your tenant, all the data stays in your environment. They can switch back to their own tenant in a few seconds for other conversations, I'm pretty sure this is what you want.

Thanks Steven, appreciate the explanation.


So I have been able to establish chat with a test user in the other office (and also other Skype users) which I now understand to be federation.


However, I have been unable to add this person to our team as a Guest user.


Method 1: Tried adding a member to the team by typing their email, get the error "We didn't find any matches. Talk to your IT admin about expanding the scope of your search".


Method 2: Sent the user the link to join our Team. Screenshots of the steps he took, which didn't work in the end. I have guest access enabled. Anything else I should be doing?




There several settings that need to be right to allow guest access in Teams, see ...


Thank you Steven. Will try these and report back.
After doing Steven's checklist, if you still can't invite guests I had an issue where I actually had to go enable it still on the old Teams settings area on the Office 365 admin portal even thou the setting was turned on in the new Skype / Teams Admin portal.

It's under the Settings > Services & Add-ins > Microsoft Teams, then selects in the drop down for license type see if guest is there, then turn on Teams for guests.

Usually this will be greyed out but for whatever reason after turning everything on and guest access not working I went back to this old setting and low and behold it let me set it and then guests worked.
Thanks all, there was one item on the checklist ("Members can invite") on Azure that I think was preventing adding users. I've now added the test user onto our team, and all seems to be working well so many thanks for everyone's help!!!

The user shows up as Firstname Lastname (Guest). Is there any way of removing the guest label?

Another thing about this solution is that the user from the other tenant is now logged in to Teams on our tenant, so they will not be able to communicate with external users via their own tenant, without switching back, right? The reason I ask is that we also aim to have videoconferences with other companies in the group via S4B/Teams, so this means they might need to switch back to their own tenant each time they have such a call. Either that or they permanently operate as a guest on our tenant.
I switch to guest tenants and join the meetings there all the time works fine. But yeah currently you have to switch tenants to chat in teams and or chat if you use their guest account in your chat. If you want to chat with their tenant account in their tenant then you need to use federation via new chat button “search externally for x.....” this will sent it externally but you don’t get the full Teams chat experience as you do with guests.

Teams to Teams federation V2 is coming which will give a better teams chat experience when using federation I believe.
That's good to know. Would Teams to Teams federation v2 allow you to add users from other tenants to your team, or would that still require guest accounts? Any idea on when that is coming?
Hi! This will still require a guest account to add members to a team from other tenant! The federation V2 @Chris Webb talks about refers to federation only! (External user chat)


I don;t believe there is anything much made public about v2 federation, other than it supporting things like pictures in chat between organisations. Microsoft are all ears at he moment for what people want more for guest accounts so I would suggest you make sire you vote or add your requirements to uservoice.


In your scenario I think guest account would be the way to go.

Yeah, v2 Federation was just touched briefly in these Teams deployment video's at this timestamp:

Said that the experience between Teams to Teams would be better as the limitations in v1 using S4B federation doens't have emoji etc. What that means as how much of the experience we get not sure, but hopefully we get inline photos and things like that at a minimum.
Really appreciate everyone's help with various areas. Unfortunately I can only mark one post as the best response, and Steven's checklist was what finally got it working. Hopefully the likes also make a difference! Thanks again.