push notification connecting error

I'm using php script for pushing notification on my application. But on following line

$fp = stream_socket_client('ssl://gateway.sandbox.push.apple.com:2195', $err, $errstr, 60, STREAM_CLIENT_CONNECT, $ctx);"

where

$ctx = stream_context_create();
stream_context_set_option($ctx, 'ssl', 'local_cert', 'ck.pem');

I get an error as follows:

Warning: stream_socket_client(): SSL operation failed with code 1.

OpenSSL Error messages: error:14094416:SSL routines:SSL3_READ_BYTES:sslv3 alert certificate unknown in /Users/amit/Desktop/Not开发者_开发技巧ificationFolder/apns.php on line 29

Warning: stream_socket_client(): Failed to enable crypto in /Users/amit/Desktop/NotificationFolder/apns.php on line 29

Warning: stream_socket_client(): unable to connect to ssl://gateway.sandbox.push.apple.com:2195 (Unknown error) in /Users/amit/Desktop/NotificationFolder/apns.php on line 29

Failed to connect 0

Do any one know how to get rid of this problem?? Beside it everything works fine.

what's your certificate password, is it given correctly and is you certificate really found in ck.pem ? How did you create your certificate?