Created a .3mf file using the slicer in bambuddy from a .stl file. I downloaded it and opened in Bambu Studio. Looks fine.
I'm connected to my printer, I can browse files on the sd card.
When I go to print the .3mf file, from projects -> Files it looks like it's downloading and then sits there waiting for the printer to respond, but it doesn't.

The window goes away and it shows as being printed in the Archives.

Any ideas what's going on?
chris