There is no connection to my android application

hello,
i am working on a project that i am using your free Web servers to host my Web site to receive and send some data to my Android application, but when i try to connect my Android to your Web server over public IP address, it gives me an error. can any one help me please ?

to use remote mysql you need to upgrade to premium.

https://www.hostinger.com/special/000webhost

if i upgraded it, can i send messages back from the server to my Android app over TCP connection? do i have to build a WebSocket server, but then i can not bind the public IP address that the 000WebHost gave me with a port number, because what i know is that, i can not send from public IP to a private IP address. can you help me please.

What exactly do you want to have as an end product?

You can probably do the same thing using some php and remotemysql no?

my project is irrigation system, i want to sense some data from hardware components, and then saving it on your website database, and there is Android application that receives these data when it is requested, and inform and request the server to do some tasks in the hardware components like open or close the valve through your server from my Android application.

use hostname and not ip address. ip addresses may change in time