Hello,
I have the same problem... I had to log in in the computer 2 with my Host/admin user first in Single Mode, and then, Change to Multiuser mode... Then, loged in in the main (hosting) computer with the User 2 to be able to use both computers and the same file at one time... I could acces today thanks to your comment, with this problem. Never happend that situation before, it is the first time in years, after update to 2021 QB version.
Good day,
CM
