Question about premium upgrade and pings

Hi and welcome to the forum

How are you trying to do it and through which software (or browser) ?
Is that txt.file stored on the server here?
and where your app is located/hosted ?

Ping doesn’t matter in this case because what you need is to use
HTTP GET request - using a browser (a device that can store cookies and run javascript)

I apologize if I misunderstood something, but this is the answer I could give based on the information you provided.