Hey developers, you may have an issue on your hands. There may be some problems with sync when Enpass is installed in a non-package manner.
I had the same problem, running Ubuntu 20.04 LTS. Initially I installed it using the SNAP system (clicked on the Ubuntu start button, searched for "software", and clicked on Ubuntu Software). It seemed to install fine and started right up without error, however while the Enpass client was running it simply would not connect to the extension on my Vivaldi browser. I uninstalled, used the apt-get instructions at the top of this post, and restarted the client. All my settings from the previous install were still there only this time everything worked out of the box.
In each case the fix was to uninstall the other package installs and install via apt-get.
Mint I believe uses Flatpak while Ubuntu 22.04 uses Snap. I know for a fact on Ubuntu 20.04 that the Snap installs use different paths for its files and does not have permission to see other folders in the user's Home directory.
This may be a problem going forward as more distros move to Snap by default. Just sayin'.