Unable to connect to Apple Push service after it worked for a long time. Nothing changed on my side

Question

I'm using Apns-PHP library to send Apple Push Notifications. It was functioning correctly, certificates fine, huge amount of pushes were sent out in the recent past.

For a while though, it cannot connect to the Apple service. This is strange because nothing changed on our side. In fact, nobody touched the server for a long while.

Do you know if anything changed on Apple's side that could prevent the connection?

Here is a log sample from my server:

Tue, 04 Feb 2014 03:54:42 +0000 NmPns[7799]: INFO: Starting Job (job ID: 581 ; env: 2)
Tue, 04 Feb 2014 03:54:42 +0000 NmPns[7799]: INFO: Preparing job - building queue.
Tue, 04 Feb 2014 04:10:38 +0000 NmPns[7799]: INFO: Built queue (device count: 421335)
Tue, 04 Feb 2014 04:10:39 +0000 NmPns[7799]: INFO: Connecting to Apple server...
Tue, 04 Feb 2014 04:10:39 +0000 ApnsPHP[7799]: INFO: Trying ssl://gateway.push.apple.com:2195...
Tue, 04 Feb 2014 04:10:40 +0000 ApnsPHP[7799]: ERROR: Unable to connect to 'ssl://gateway.push.apple.com:2195':  (0)
Tue, 04 Feb 2014 04:10:40 +0000 ApnsPHP[7799]: INFO: Retry to connect (1/3)...
Tue, 04 Feb 2014 04:10:41 +0000 ApnsPHP[7799]: INFO: Trying ssl://gateway.push.apple.com:2195...
Tue, 04 Feb 2014 04:10:41 +0000 ApnsPHP[7799]: ERROR: Unable to connect to 'ssl://gateway.push.apple.com:2195':  (0)
Tue, 04 Feb 2014 04:10:41 +0000 ApnsPHP[7799]: INFO: Retry to connect (2/3)...
Tue, 04 Feb 2014 04:10:42 +0000 ApnsPHP[7799]: INFO: Trying ssl://gateway.push.apple.com:2195...
Tue, 04 Feb 2014 04:10:43 +0000 ApnsPHP[7799]: ERROR: Unable to connect to 'ssl://gateway.push.apple.com:2195':  (0)
Tue, 04 Feb 2014 04:10:43 +0000 ApnsPHP[7799]: INFO: Retry to connect (3/3)...
Tue, 04 Feb 2014 04:10:44 +0000 ApnsPHP[7799]: INFO: Trying ssl://gateway.push.apple.com:2195...
Tue, 04 Feb 2014 04:10:44 +0000 ApnsPHP[7799]: ERROR: Unable to connect to 'ssl://gateway.push.apple.com:2195':  (0)
Tue, 04 Feb 2014 04:10:44 +0000 NmPns[7799]: ERROR: Aborting job! Cannot connect to server. Message: Unable to connect to 'ssl://gateway.push.apple.com:2195':  (0)

Answer 1

Maybe your certificate has expired? Go into your developer console, in the Certificates section. Look into the app id of your app if the push notifications are "Enabled" or "Configurable"