If the trial warning persists after adding the code, old build artifacts might be caching the license validation failure. Close your Integrated Development Environment (IDE).

The "Syncfusion trial license key fix" is version-sensitive.

Open your main.dart file and add the registration inside the main() function:

No, the application will usually continue to run, but it will display disruptive trial watermarks, popups, or console warnings. To remove these visual blockers, you must generate a new key or purchase a commercial license.

Sometimes, the development server caches the old "trial" state. After applying the key, perform a Clean and Rebuild of your solution and clear your browser cache.

The RegisterLicense method was never called in your application startup.