Is it possible to use KeepassXC browser extension on Firefox flatpak version?

Both KeepassXC and Firefox are installed via flatpak. In the KeepassXC Browser Integration tab, it sayts that it doesn’t support snap, but flatpak is not mentioned. When I try to connect to the database I got this message “Key exchange was not successful.”.

Apparently some extra-configuration is required . See Enabling KeePassXC Add-On for Flatpak Firefox |