Issue with texting function

Hello, So I have a problem with the texting function on app inventor I am currently following a course from udemy and I was working on an app that automatically replies to messages with a set time and a reply message. However, the app doesn't reply to the texts I have sent. I have tried using multiple apps to send messages but that didn't work. So I am confused is this problem related to app inventor or my phone?

Welcome SwanRox.

What you can do with the Texting is described in this documentation. Have you read it?
or done this tutorial

No Text While Driving - MIT App Inventor , The tutorial shows how to auto reply to texts sent.

Be aware, some changes to the Texting component were made after the tutorial was posted. You have to read the document to make sure you set ReceivingEnabled

If set to 1 (OFF) no messages will be received. If set to 2 (FOREGROUND) or 3 (ALWAYS) the component will respond to messages if it is running. In the case of 2 (FOREGROUND), messages received while the app is not running are discarded. In the case of 3 (ALWAYS), messages receive while the app is not running will show a notification. Selecting the notification will bring up the app and signal the MessageReceived event. Messages received when the app is dormant will be queued, and so several MessageReceived events might appear when the app awakens. As an app developer, it would be a good idea to give your users control over this property, so they can make their phones ignore text messages when your app is installed.

and make sure you use Companion 2.6u so you have access to the Blocks that permit it to automatically send messages.. One of these explains the issue