What files does ios-php need for Apns?

IOS developers said that as long as a suffix is p12, I can convert this p12 to pem and write a sending test in PHP, but the prompt is: Unabletoconnect: tls: gateway.push.apple.com: 2195: 2 (stream_socket_client (): Failedtoenablec... IOS developers say that a suffix named p12 is enough.

I converted this p12 to pem and wrote a test code in PHP, but the prompt is:

Unable to connect: tls: // gateway.push.apple.com: 2195: 2
(Stream_socket_client (): Failed to enable crypto)

I have said on the Internet that a certificate and a private token are required, that is, two files. But some materials have not said this, so I have not figured out what files are needed.

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IOS developers say that a suffix named p12 is enough.

I converted this p12 to pem and wrote a test code in PHP, but the prompt is:

Unable to connect: tls: // gateway.push.apple.com: 2195: 2
(Stream_socket_client (): Failed to enable crypto)

I have said on the Internet that a certificate and a private token are required, that is, two files. But some materials have not said this, so I have not figured out what files are needed.