How to correctly implement the Billing API in my app?

[AnEpicName]

Hi,

I'm trying to implement the Billing API in my app and I'm having trouble with the confirmationUrl that is generated when I create a subscription. I'm trying to redirect my app to that URL when someone creates a subscription, but after that I'm getting the error "mystore redirected you too many times". Am I doing this wrong? Because I just went to the URL manually and it works fine, and the subscription appeared in my dev profile.

I'm not very clear about this step, and I'm a little stuck in this.