WebViewer Communication Works in Thunkable Live but Fails in Compiled APK

Hello, I am developing a vacation management system that includes a calendar. The calendar is displayed in a WebViewer inside Thunkable, and it communicates with the app using the ThunkableWebviewerExtension.

The problem is that in the compiled version (APK/IPA), the WebViewer does not receive messages from Thunkable, or it fails to send messages back. However, everything works perfectly in the Thunkable Live Test.

Here is the code I am using for the webpage:
GitHub Link

Has anyone encountered a similar issue? How can I ensure reliable communication between the WebViewer and Thunkable on both Android and iOS?

Thank you in advance!