"Someone has already set up Teams for your organization"

Hello joshuamartin2045 

Hope you are well (:

There is an article with three possible solutions:

https://docs.microsoft.com/en-us/microsoftteams/troubleshoot/teams-sign-in/someone-has-already-setup-teams

If this do not resolved your issue try do admin takeover, could be that someone set up for example a power bi free account with that domain!

https://docs.microsoft.com/en-us/microsoft-365/admin/misc/become-the-admin?view=o365-worldwide

If anyone knows of such a policy I would like to know about it as well (:

Hi joshuamartin2045 ,

I would start by taking a look at:

https://docs.microsoft.com/en-us/microsoftteams/troubleshoot/teams-sign-in/someone-has-already-setup-teams

But unfortunately the answer is not easily.

Thanks

Henry