APNS + PHP “stream_socket_client(): Failed to enable crypto”

Question

I\'m having trouble with using APNS with PHP and getting the following message:

stream_socket_client(): Failed to enable crypto

The problem

Answer 1

I have this problem because I foolishly forgot to include the file extension (.pem) when supplying the file path for local_cert.

Answer 2

In my case, the issue was with my mac (OSX Sierra). I uploaded php and cert to my server, ran it, and the notification was delivered.