Pls contact the hosting provider for more information on how they are caching the server… we have no way to know how they are optimizing the server.
1) How is a child activated?
After adding child theme to your themes folder through FTP
You need to go to your WP admin panel and activate the child theme in appearance> themes ,just like a normal wordpress theme .
2.Pls insert the below custom CSS in themeoptions –
.button.get-app {
border: none;
}