You will have to test this example using the test server mentioned in Envió de mensaje directo en Android 12, FLAG_IMMUTABLE until MIT fixes the Texting component (SMS messaging ) because the SMS component is presently not working correctly. When will this be fixed on the main server? I do not know but guess it might get fixed with the next App Inventor update (hopefully within a few weeks).
You will have to test this example using the test server mentioned in Envió de mensaje directo en Android 12, FLAG_IMMUTABLE until MIT fixes the Texting component (SMS messaging ) because the SMS component is presently not working correctly. When will this be fixed on the main server? I do not know but guess it might get fixed with the next App Inventor update (hopefully within a few weeks).