Hello Hua,
Please make sure that you have set it up properly by following the instruction manuals provided together with the Expert Advisor. Mainly, check if you have enabled Automated Trading and allowed DLL imports.
Also, check if Telagram.Forex app has made a connection with MT4. In your MT4, in the “Experts” tab, at the bottom, you should see a message “New client connection” that indicates a successful connection with the app. Let us know if you still experience some problems.
Telegram.Forex