Importing Canon MV800i camcorder into iMovie

I’m trying to digitise camcorder footage & was able to import some video (with the use of 3 adapters linked end to end: mini DV to firewire 400 -> firewire 400 to thunderbolt -> thunderbolt to usb c) into iMovie a few days ago. As soon as I connected the canon MV800i and opened iMovie the camera showed up in the import list straight away. However when I reconnected it today nothing happens, iMovie doesn’t see the camera. Confused and frustrated! The setup is identical to a few days ago, the adapters/cords are all brand new, I’ve tried reconnecting and restarting everything multiple times.. what is going on?!