Tray menu caracters shown as tofu blocks ▯▯▯▯▯▯▯

Hi there everyone, I’m developping this app called Muezzin ( And the caracters in the tray menu are shown as Tofu Blocks, something like this ▯▯▯▯▯▯▯.

I’m building the snap with electron-buider with these options in the package.lock:

"snap": {
  "confinement": "strict",
  "summary": "Islamic prayer times application",
  "grade": "stable"

These are the messages I get when I launch the app:

Gtk-Message: 11:18:52.252: Failed to load module "xapp-gtk3-module"
[60465:0410/] Gdk: gdk_window_thaw_toplevel_updates: assertion 'window->update_and_descendants_freeze_count > 0' failed

Yes, the unity7 interface is enabled by default thanks to electron-builder:

I’d really appreciate your help. Have a great day !

Tried it on XFCE, and the tray menu works properly. But on qTile it’s still broken. No clue why.