Flatpak Electron app build failed


I have been trying to build Flatpak app using Electron Sample App here: Electron — Flatpak documentation

I follow the guide one by one. The sample app is being build successfully.

Now next step is I want to generate a Single file bundle (Single-file bundles — Flatpak documentation) and failed with severl attempts for last 3 days.

any help will be much appriciate.