If you have a Microsoft account, you should have access to the free tier of Microsoft 365 (web apps, mobile apps, limited OneDrive storage, etc.) which I think can be used to log in to Teams and attend meetings created by other people.
But I’m not completely sure. All of my Teams experience is on Windows, via my employer’s PC, logged in to my employee Microsoft account.
We have five Office 365 licences for our business but I refuse to pay extra for Teams because all we would ever use it for is virtual meetings - the rest of its functionality has no value for us. However since they started charging for Teams it has been a real nuisance and I cannot guarantee that it will work - sometimes it does and sometimes it doesn’t. I now tell people never to send me meeting invitations with Teams but to use Zoom instead, which works really well.
Installing MS Edge worked for me. I now have Edge in the Dock. I simply drag the URL from the invitation email onto that Edge icon. Edge opens and asks if I want to open the Teams app. Agreeing to this starts Teams and allows me to successfully join the meeting.
Edge is available for High Sierra up (I am running Mojave).
@mpainesyd I don’t know if this addresses your Firefox issue, but I noticed the following bug fix in the Firefox 117.0.1 Release Notes:
- Fixed a bug causing links opened from outside Firefox to not open on macOS (bug 1850828)
I doubt if it will have any effect. The problem, as I understand it, is that Safari and Firefox do not have Chrome-related components that allow (limited - I hope!) control of your computer from the MS Teams app launching website. There are other websites around with the same limitations.
As I indicated above, I have installed Edge solely for the purpose of launching the Teams app. But even that failed on me the other day and I was forced to join the meeting with the Edge browser.
I am finding I need to try and join Teams meetings at least 5 minutes ahead of time to allow for something no longer working, or a forced MS software update.