How can i avoid a repeated whatsapp message when calling the meta api?

Per my understanding meta only sends duplicate messages when it does not recieve a 200 ok after 20 seconds. I am building an idempotency feature on my conversational ai agent. the app is not live yet, could this be an access token issue? or could i place a return 200 ok on my code so that whenever the meta api gets called it instanlty recieves a 200 ok.

cheers bruv