Immediate `WebUI Error: Connection with the backend is lost`

[Rodent-Nick]

Thank you for this wonderful package! It works wonders on Windows 👍

However, when I build the library on Linux, I constantly get this error:

This error reoccurs every time, regardless of which version of WebUI I am using. So far, I've tested with the following version:

• The one I clone directly from the code repository (commit e11d81f)
• Release 2.5.0-beta.3 (https://github.com/webui-dev/webui/releases/tag/2.5.0-beta.3)
• Nightly Release 2026-03-23 (https://github.com/webui-dev/webui/releases/tag/nightly)

The versions above all create the same error. When testing with the nightly release, I use a custom file handler to show me what had failed to load. It turns out a /_webui_ws_connect is constantly being loaded and failed.

I am using C++ as my programming language, GCC and G++ version 13.3.0. My computer has Firefox installed, but I am using GTK WebView by installing the libwebkit2gtk-6.0-dev and also libwebkit2gtk-4.1-dev before building the WebUI library, and calling the function win.show.

This issue sounds similar to this issue #688. However I cannot solve the issue even with info provided there.

Thank you in advance for helping me 🥲 .