Allow Guests to Share Screen
While guests can now join a Team meeting, there is no "promote to presenter" option to allow them to share their screen. Without this, I'm forced to fall back to Hangouts or Zoom.
Matthew Jarsky commented
Org-wide settings > Guest access > Meeting > Screen sharing mode: Toggle it on.
Daniel B commented
Microsoft is working on this one. Better to track/vote on this one: https://microsoftteams.uservoice.com/forums/555103-public/suggestions/36131932-allow-anybody-to-share-their-screen