Premiere Pro doesn't recognize insv files

I have a Mac and Premiere Pro 2020. I have installed Insta360 Studio 3.5.8 and the associated Adobe PP plugsins as well as the GoPro FX Reframe plugin. But when I try to import my Insta360 video files, I get the message "The file format is not supported." What is happeneing and how can I fix it? Thanks!