I have been transfer projects from a free account to a organisation account although the process was a bit complicated I managed to do all except one for some reason.
I used the sam method select the - Project > Settings > Transfer > Next > add a link (paste the URL to from project folder I want to transfer to and Figma verified it.) fill in email and hit enter.
Then the error message “You cannot transfer to this organization at this moment. Please contact support for more details.” pops up. What could be the issue here?

