Hey @Furgonetka.pl! I looked into this error and from what I can see "App Bridge Next: missing required configuration fields: shop" is typically thrown by the older npm-based @shopify/app-bridge package (v3.x), not by the current CDN-hosted version. So one thing to check is whether your app still has the old npm package installed or is calling createApp() somewhere in the code. If so, the old initialization would be running alongside the CDN script, and those two approaches can’t coexist.
The current CDN version of App Bridge doesn’t need shop, host, or any manual createApp() call. It picks everything up automatically from the admin iframe context.
If you do find old App Bridge code in your project, the migration guide walks through removing it step by step. Once you’re only using the CDN approach, use your app on a dev store in an incognito window, then give the checks some time to pick up the new telemetry (can take up to a couple of days).