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November 09, 2021, 08:00 AM - 12:00 PM (PST)

Teams room with External invitation

Occasional Contributor

I have the project to set up a "Teams" meeting room with a Polycom room equipment that will be certified Teams soon: poly studio X50.

I'm wondering how "Click to join" works when a person receives an invitation from outside the company and the room has not been invited (only the user).

Does the user have to transfer the external Teams invitation to the meeting room email? I don't really understand the Workflow that can be used to make the use of my rooms simple.


15 Replies

@jfrobs You have probably turned off so that external users can't e-mail to the room accounts mailbox (that is default) so the best way is that an internal user forwards the invite to an room mailbox. Note that the confirmation sent back from the room mailbox will be sent to the organiser (external) of the meeting and not to the one that forwarded the meeting.

@Linus Cansby This is the workflow I had thought of for my users. But I was wondering if it was possible when sending an external invitation to send the invitation back to a device.

best response confirmed by jfrobs (Occasional Contributor)
Can you explain more "to send the invitation back to a device."

When you forward the external invitation to your room account mailbox (that your MTR device uses) it will reply if it did accept the meeting invite or not to the person that scheduled the meeting (the external person in this case).

@Linus Cansby  I am having the same issue with coincidentally the same hardware, PolyX50.   I understand that the response "should" go back to the meeting originator but it does not seem to accept and respond to anyone outside our organization, or me as the person who forwarded the request to the room.   I have asked our IT guy to confirm the setting on the room's email.   He said that he spoke with Microsoft and was told that in order to make a meeting request you either need to be within the organization or be a guest.   Can you confirm this or make a suggestion of how to accomplish forwarding an external Teams meeting request to our Teams Room?   Your prior post seems to indicate that it is a simple setting to allow external requests.  Perhaps a screen shot of the setting that I can share with the IT guy? 

@pdnielsen What they have to do is to turn on "ProcessExternalMeetingMessages" for that room mailbox, that is done with Set-CalendarProcessing.


Set-CalendarProcessing (ExchangePowerShell) | Microsoft Docs

@Linus Cansby Thank you.   It now accepts the invitation and shows the meeting organizer's name on the screen as it should just like when people from within our organization schedule a meeting.   The problem now is that there is not a Join button on the screen and the Join button on the TC8 does not function.   I have not found a setting within the Poly Native Teams App for internal/external.   Do you know anything about the Poly App or do I need to go to the Poly forums? 

@pdnielsen Great, yes check with Poly about the Poly App.

Not sure if there is a restriction with the Poly but make sure you also use the powershell command Set-CalendarProcessing to set these options on the meeting room mailbox otherwise the join button may not appear as you've found..
-DeleteComments $false -DeleteSubject $false

Another thing to check. Are you using SafeLinks as part of Office365 ATP? If SafeLinks is rewriting link URLs on incoming emails from external addresses (even internal depending on how its been configured) then the MTR devices will not recognise the appropriate link in the invite as being a Teams link and will therefore not show a 'Join' button. The solution is to whitelist the applicable domain/url in the SafeLinks policy.

@pdnielsen We had the exact same issues with a new Yealink bar, no join button on the external touch display (invite from outside of the company's AD) or if the join button is there (from inside the AD) it is not working.


For the first problem we got a Hotfix firmware from Yealink and they are working on the second problem so most likely a MS Teams issue rather than hardware...?!?!?


The Yealink has a "Proximity" join which is convenient so we can join the meeting on a phone or Mac/PC  while being in the room and then "add a room" which transfers the meeting to the room.

So did anyone get a fix on the "join" button not working with a external meeting invite?

having the same issue with Yealink VC210's. The join function doesn't work. Even if I take the link to the meeting and create an entirely new meeting from my account using that external Teams link. @MFarah 

Join buttons don’t show for external invites without safe linking everything. The best way atm is allow comments on the invites and train users to click the meeting then just click the link in the body of the invite. That’s only thing I could figure out for now.

Microsoft makes this so unnecessarily difficult. My people have been tied up for a lot of their time trying to troubleshoot this idiotic problem. We paid a lot of money for a Logitech rallybar and tap app and it works nicely internally, but not being able to use our meeting room when we have an externally-generated teams meeting is insane. What is worse is there seems to be no simple setting to resolve this anywhere. Surely there is some simple setting to allow this?

I had same issue with Teams Rooms and Yealink touchscreen system.


I found a work around in 6 simple steps:

  1. Accept external calendar invite on your personal email/Teams account
  2. Join Teams meeting from laptop or mobile
  3. Invite the desired Meeting room into the Teams call
  4. Accept the call from the touch panel on the table in the meeting room
  5. Leave the meeting with the personal account from laptop or mobile
  6. Continue the meeting using the  Screen and Audio/Video system in the room. (the meeting will continue between the external user and the Teams Room System)