Chromium doesn't open e2dk files on Amule, Chrome (flatpak) does

Hi guys, I have this annoying problem that forces me to install Chrome just for this reason. Basically when I want to add an e2dk server on Amule, I am forced to use Chrome because when I click on the browser on the server link, it automatically adds itself to Amule. If I open it with Chromium (official repository), it opens me the dialog box that says “open with xdg-open” to ask me to open it but then it tells me:

Unable to reach the site
Check for typos in ed2k.

Anyone know how to fix?