DV import from Canon tape camera stops intermittently
I've connected my Canon video camera via DV connector/Firewire400 to FW800 adapter/Apple FW800 to Thunderbolt connector to my 2014 iMac. FCPX sees the camera (Canon Optura300) and begins importing, BUT after anywhere from a few seconds to several minutes the process stops. The same thing happens with iMovie. So basically the system works except for the stopping. Ideas?
iMac with Retina 5K display, macOS 10.14