I’ve verified my solution is functionally correct against the exact official test code (fetched /_api/package.json, /_api/app, and / directly — all return the expected values: pug in dependencies, view engine: "pug", views: "./views/pug", and the home page renders FCC Advanced Node and Express / pug-success-message correctly).
I tested this on 3 separate hosting setups (Render with Node 16 pinned, a fresh Render deploy, and an official GitHub Codespace at *.app.github.dev) — all pass when checked manually via curl/fetch. Yet clicking “I’ve completed this challenge” always returns “Failed” on all 5 hints, instantly, in Chrome, Edge, AND Firefox (all three browsers, ruling out a browser-engine-specific cause).
I found a related report from March 2026 (topic #780953) where a moderator (Anna) confirmed a DataCloneError: Error executing 'postMessage' on 'Window': The URL object could not be cloned bug affecting project-challenge submissions, with a fix “in the works” but never shared publicly. Is this still an open issue? My solution link: https://fluffy-waffle-jjx4p79qgxgvc7rj-3000.app.github.dev