I also have the same problem in Ubuntu. The supposed deb package does not work. If you try also to install in the version from the software installer of ubuntu, it saids that you have not all dependencies. I compiled the version and it runs but never refresh uploaded files. I tried in many machines and is the same, so it seems to be a problem of Ubuntu after 2020. I have been waiting months for a soultion but I think that eventually I will stop using dropbox.