External Guests being invited to channel meetings

[stevecousins]

When I create a new channel meeting and invite specific members of the channel, the invite is created and the attendees receive the meeting notification, however, external guests who are members of the Team but are not part of the attendee list are also being invited.

Is anybody else having this problem?

[#2]

Hi, when you have a meeting in a channel, everyone in the team will be able to see it and join it in that channel. That’s by default.

[#3]

@ChristianBergstrom I understand that everybody can see the channel meeting and can join is they choose to.  My problem is that external (Guest) members of the Team that are NOT in the Required Attendee (below) list are also being invited.  Normal members (non-guests) that are not in the required attendee list are not seeing the same behavior.  

[#4]

Ok, I understand. My best guess here is the fact that guests doesn’t have the ability to create meetings or access schedules and therefore are being notified about the channel meeting.

You can always ask the Microsoft support for an official answer by creating a support ticket (or someone with access can do it for you if you’re not an admin).

btw, this is a great article on the topic https://office365itpros.com/2020/03/31/invitations-teams-meetings/amp/

[#5]

@stevecousins are you still having this problem? We just started having this problem recently. If you were able to solve this problem, how did you do so?

[#6]

Hi @stevecousins, same issue here...I tested it with a college from a different organisation. This behavior is very annoying and frustrating because it leads to very much confusion especially between different organizations :(

[#7]

"All members of the team are automatically invited."
Source: https://docs.microsoft.com/en-us/microsoftteams/tutorial-meetings-in-teams?tutorial-step=2

"Note: When you have a meeting in a channel, everyone in the team will be able to see it and join it in that channel. "
Source: https://support.microsoft.com/en-us/office/schedule-a-meeting-in-teams-943507a9-8583-4c58-b5d2-8ec82...

[#8]

This is not strictly true. If I enter named channel members in the 'Required' field, only those entered in are notified, however, everybody who is a Guest is also invited even though they are not in the 'required' field. As an example, if I had a team with 4 members, Name1, Name2, Name3 and Guest1 (Guest1 is the Guest in the Team)

I then create a channel meeting and enter Name2 in the Required field. When the invite is sent, the invitation will be sent to Name2 AND Guest1. You are correct, anybody in the team can join and see the meeting (which is expected behavior) but the invitation should only be sent to those in the Required field.

Does this make sense :)

[#9]

@stevecousins I totally agree. @Tiago Roxo you did not quite get the whole picture of the problem and its consequences here ;)

Especially the way the system behaves differently between users of the own and users of a different organization (so called "Guest"). 

[#10 · Accepted solution]

@ongrieh , @stevecousins I have been chasing this problem as well. What I have figured out is that behind the scenes of the Team is a MS365 group and all Guest Users are automatically designated as 'Subscribers' of the group, regardless of team setting on "AlwaysSubscribeMembersToCalendarEvents" and "AutoSubscribeNewMembers". I presume this is because they can't directly interact with the Team/Group and self-subscribe or join channel meetings ad-hoc. However, this is not ideal because guests then get invited to _every_ channel meeting without explicitly inviting them.

The only way I can find to remove guests as subscribers is via PowerShell. You can view group/team Subscribers with Get-UnifiedGroupLinks -Identity [team name] -LinkType Subscribers. You should see the Guest accounts listed as 'MailUser' recipient types with #EXT# on the name. You can remove these with Remove-UnifiedGroupLinks -Identity [team name] -LinkType Subscribers -Links [Name]. Allow a few moments for the subscriber list to update.

This does not remove guests from their Member role, but now they won't be email-invited to every channel meeting. I haven't confirmed it yet, but it is possible that Guest Accounts get re-subscribed from some unknown trigger. That plus additional guests getting auto-subscribed necessitates creating a script to routinely unsubscribe guests.

Microsoft should fix Teams to honor "AlwaysSubscribeMembersToCalendarEvents" and  "AutoSubscribeNewMembers" on Guest accounts.

[#11]

@candera 

Very same issue here. Thanks for posting the workaround. Have you confirmed if the guests get re-subscribed?

I'm also weighing up what is the biggest headache, having to tell the guests not to join the meetings or removing notifications from them altogether, meaning they will potentially miss conversations they are tagged in. Would be interested to hear your experience with this?

[#12]

@iamatechpm  - The guest account has not been re-subscribed, which is good news. I think I wasn't tracking some testing very well and was fooled into thinking it might have happened.

I think removing the subscription is the best action. Telling someone to ignore may end up with missed meetings they were intentionally invited to and still joining meeting they don't need to. These have both happened to me with my guest account.

I did test that channel mentions and @ mentions will still show on the guest account in teams.

[#13]

@candera 

Which permissions are needed to execute the PowerShell script? Is this something only the IT can do or can this been executed by a teams owner? 

[#14]

@HeinzelAlex It's not possible to do with Team Owner rights, needs some Exchange Admin permissions.

[#15]

As Steven noted it does require some Exchange permissions. You can return a list of all Roles that can run an Exchange PS command as outlined here: https://learn.microsoft.com/en-us/powershell/exchange/find-exchange-cmdlet-permissions?view=exchange... There are a number of non-admin roles that could be used.

Microsoft has since added "Shared Channels" which I recommend looking at for any partners you may collaborate regularly with. These allow you to add External MS users as members of a channel and the channel will appear in their native organizations team, without having to switch to a guest account. I haven't tested, but it's possible this setup would honor the Disable AlwaysSubscribeToCalendarEvents flag.

[#16]

@stevecousins @candera 

I found an alternative solution for this bug, it doesn't depend on administrative privileges or even microsoft's will to definitively fix this bizarre bug, it just depends on the user's own email rules configuration (guest).

This varies depending on the mail server, for example in gmail , ask the user to put the following rule/filter (copy the code below and paste it in the field: "has the words"):

({to:(@domain_of_emails_received_in_groups.com.br) AND to:-guest_mail OR cc:-guest_mail}) {filename:vcs filename:ics}

Then make this filter (rule), mark emails as read + delete them. This will do. Because all invitations that arrive at the guest account, in which the guest is not invited, will be automatically discarded.

If your guest uses an OUTLOOK account, it partially solves the problem. Ask the guest to create a rule in outlook like the print below (you can fill in the domain instead of the group domain):

Why does it partially resolve in outlook? The guest will not receive email notifications of new meetings that do not interest him (who was not invited), however, even if these emails are deleted, outlook keeps the event in the user's calendar with tentative status, so he will receive notifications when you are close to the start of meetings.

If anyone manages to circumvent this other problem. Please let us know.

For other email providers, it works the same: just create an email rule.