I have created Site Web through Flutter Web & AWS available from https. But no answer from php reading Mysql – Apache

I have created Site Web through Flutter Web & AWS available from https. But no answer when I run php reading Mysql database
flutter code :
In http Uri url = Uri.parse("http://www.paulcode.com/db.php");
http.Response response = await http.get(url);

in https it doesnt work while others content is available
in http it works

I use apache2 on ubuntu
I have no idea where to investigate. Thanks by advance