A notify where to insert the Pin appears, but disappears too fast for me to type the code in.
I tried to solve this problem using the notification applet, and it worked. I can type my Pin in, but... there's no way to input it. Hitting return doesn't work, there's no "Ok" button, there's... nothing.
And, right after the notification with the Pin in disappears, system crashes.
Inspecting what appears when it happens, it seems that it is caused by Cinnamon.
This bug was already here in the earlier version of Cinnamon and I notified this issue to the team, but it still hasn't been solved.