Hi @Martin_Faustmann ,
What account did the other party add to their Teams Team? As the normal sequence of events would be:
The Org that does have Teams would add in say bob@outlook.com
It would detect that it is an external user
The external user would receive an invitation in the form of an email
It would at this stage realise that this is a non M365 based domain and either at this stage still allow to make use of as it is an Outlook.com (Microsoft) account but if it was say bob@gmail.com it would give the option to create a Microsoft account but make use of bob@gmail.com as an alias.
They would then complete the invitation and when accessing Teams, providing they were not a member of any other Orgs go straight in or have the option to switch between Orgs they have been added as a guest to.
So were no invites received? If you have just created Microsoft accounts, then I would ask for the Meeting hosts, within there Team Org to add in those accounts you have just created.
Now the above is all working on the basis that they are being added into a Team, the other possibility is that they have just been added to a Teams meeting, where they have been added as a participant and it is not bound to a Team. So similar to a regular Outlook meeting. Again I would double check what account has actually been added to the meeting for participants.
Thanks
Henry
