Today I was hosting a MIRO session with 13 participants. I mailed everybody a link to the session, but one participant, and one only , ended up in a wrong session/on another board. Closing down the browser and doing it all over didn’t solve the problem. What to do?

Here are two problems:

1: One of my participants can’t join the board

2: If one of my participants can join a foreign board, others can join my board. And I don’t want that to happen. Ever.