Push notification reaches APNS, not delivered to an iOS device

ionic-v1
1

I am using node-apn to send notifications to APNS. I assume that they
are successfully delivered to APNS, feedback is always empty and
library emits “transmitted” event. Notification looks like:

var pushMessage = new apn.Notification({
        contentAvailable: 1,
        alert: {
            title: chatName,
            body: text
        },
        payload: {
            chatID: chatID,
            username: username
        }
});

Cert.pem and key.pem are correct, it was checked with the openssl command.

Phonegap-push-plugin is used to integrate native SDK, which works for Android, but not for the iOS.

I am using AdobePhoneGap build to build my app.
I have followed countless tutorials and checked every step many times,
if someone has any idea what could be wrong please let me know. If any
more information is needed let me know.