Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi JayB-Au,
Where do you download the Microsoft Teams app? Please click the below and choose Mac to download the .dmg file to install Microsoft Teams on your Mac:
https://teams.microsoft.com/downloads
I have just downloaded it from the link above and installed successfully on our Mac machine with the same OSX version Sierra 10.12.3. If you download Teams from the correct link, to look into the issue, we want to see the screenshot of the error you have received.
Thanks,
Lance