Using Classic Outlook on Windows for personal email, calendar, and contact management
... changing this setting in Edge, which I never open or use, has cured it for me.
Alex_414x, do you mean you change your default browser to Edge? I tried this (with Chrome and Firefox) but it still opens the default browser (and requires a login because it doesn't recognize it). What settting are you referring to?
Sorry I thought my reply picked up the picture comment I was replying to but I now see I didn't tick the box!
It's a setting in Edge; I still use Brave as the default browser, I didn't change that.
I opened Edge and went to the settings within Edge not the PC settings:
settings/system & performance/Continue running background extensions and apps when Microsoft Edge is closed (it's near the top) - I switched this off and it worked for me. I didn't have to fiddle with the calendar or teams settings at all.
Screenshot of the reply that fixed it for me: