External users have difficulty joining the team.
I've invited external users several times, (external users are allowed for Teams in the Office365 settings). The Teams app allows me to add users, sends them an email with a link, but when they click the link, launching their Teams app, an error pops up saying that they need to be invited to Teams. Although... they just clicked on an invitation link.
I have been trying to set up teams with my students for a while. All the teachers have 365 accounts, but the students don't and I have tried and tried in vain to set up classes through teams. So we had to go back to zoom, which makes it so easy for anyone and everyone to use.