How to set up Push Notification from a third-party developer account?

Question

iOS

There are many tutorials on setting up, but all of them are about setting up notifications from scratch and from your account. This is the second time I've run into a setup problem and would like someone to explain what I'm doing wrong.
I have at my disposal an application on which it is necessary to test notifications, but I did not develop and the certificates are not mine.
I add an account to my XCode so that I can run the application without changing the Bundle ID and work from that account
I create a second notification certificate for myself (Development), since I cannot add the first one to my KeyChain
I create a Provisioning Profile and work using it
Back -End upload new notification certificate .p12 (used by Parse.com)
As a result of testing, notifications go away, but the phone does not accept them, and if I send them from the dashboard to my ID token, notifications do not come either.

Answer 1

What does parse write? If something is wrong with the certificates, the aps server throws an "Invalid token" error, parse should display this somewhere.
In general, the problem often lies in the fact that the certificate used to sign the application and the certificate for push notifications have different private keys.