Verify Webhook URLs and Server Configuration Webhook URL: Ensure that the webhook URLs you have configured for incoming messages are correct and match the ones used for other successful webhooks. Endpoint Availability: Check that your server endpoints are up and running, and can handle incoming POST requests from these webhooks. Security Settings: Make sure that any security settings (like firewalls or API gateways) are not blocking requests from the webhook sources. 2. Check Webhook Subscription and Permissions Webhook Subscription: Double-check that your app is subscribed to the correct webhook events for incoming messages. Verify this in the respective platform dashboards (Facebook Developer Console, WhatsApp Business API, etc.). Permissions: Ensure that your app has the necessary permissions to receive incoming message events. Sometimes, permissions need to be explicitly granted. 3. Debug Webhook Requests Logging: Implement logging in your webhook endpoints to capture all incoming requests. This can help determine if the requests are reaching your server. Mock Requests: Use tools like Postman or CURL to send mock requests to your webhook endpoints to ensure they are functioning correctly. 4. Verify App and Token Configuration Access Tokens: Make sure that your access tokens or API keys are correctly configured and have not expired. App Review: If your app is still in development mode, ensure that it is correctly configured for the environment you are testing in (development or production). 5. Review Platform-Specific Documentation Facebook Messenger: Verify that you have correctly set up the webhook in the Facebook Developer Console under the Messenger settings. Check the "Webhooks" section and ensure the subscription to the messages and messaging_postbacks fields. Instagram: Check the Instagram Graph API documentation to ensure you have subscribed to the messages webhook and that your endpoint can handle these specific events. WhatsApp: Review the WhatsApp Business API documentation to ensure your webhook configuration is correct and your server is prepared to handle WhatsApp-specific webhook payloads. 6. Platform-Specific Testing Tools Facebook Developer Console: Use the "Webhooks" section to re-test and re-configure the incoming message webhooks. Check for any error messages or logs that can give more context. WhatsApp Business API: Use their API tools to test webhook configurations and ensure the webhook URL is correctly set.