Paypal Sandbox IPN在IPN模拟器中工作但不在事务中工作

Question

我有以下表单在沙盒paypal帐户中发送数据

<form name="paypal_form" action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
    <input type="hidden" name="item_name" value="bronze">
    <input type="hidden" name="business" value="xxx@gmail.com">
    <input type="hidden" name="src" value="1">
    <input type="hidden" name="sra" value="1">
    <input type="hidden" name="cmd" value="_xclick-subscriptions">
    <input type="hidden" name="no_note" value="1">
    <input type="hidden" name="no_shipping" value="1">
    <input type="hidden" name="currency_code" value="USD">
    <input type="hidden" name="a3" value="0.1">
    <input type="hidden" name="notify_url" value="http://mywebsite.com/return.php?action=ipn">
    <input type="hidden" name="cancel_return" value="http://mywebsite.com/return.php?action=cancel">
    <input type="hidden" name="return" value="http://mywebsite.com/return.php?action=success">
    <input type="hidden" name="rm" value="2">
    <input type="hidden" name="t3" value="D">
    <input type="hidden" name="p3" value="1">
</form>

我遇到问题，因为IPN模拟器给了我正确的通知，但在交易中它不起作用。我也检查了IPN历史记录，但也没有发送。

我已将IPN通知设置设置为“开启”，并在沙盒商家帐户中设置notify_url。

以下是我的IPN侦听器代码：

class ipn {

    var $last_error;
    var $ipn_log;
    var $ipn_log_file;
    var $ipn_response;
    var $ipn_data = array();

    function __construct() {

        $this->paypal_url = 'https://www.sandbox.paypal.com/cgi-bin/webscr';

        $this->last_error = '';

        $this->ipn_log_file = 'ipn_log.txt';
        $this->ipn_log = true;
        $this->ipn_response = '';
    }

    function validate_ipn() {
        $this->paypal_url = 'https://www.sandbox.paypal.com/cgi-bin/webscr';
        $url_parsed = parse_url( $this->paypal_url );        
        $post_string = '';
        foreach ( $_POST as $field => $value ) {
            $this->ipn_data[ "$field" ] = $value;
            $post_string .= $field . '=' . urlencode( $value ) . '&';
        }
        $post_string.="cmd=_notify-validate";        
        $fp = fsockopen( $url_parsed[ 'host' ], 80, $err_num, $err_str, 30 );        
        if ( !$fp ) {
            $this->last_error = "fsockopen error no. $errnum: $errstr";
            $this->log_ipn_results( false );
            return false;
        } else {
            $this->ipn_response = file_get_contents( $this->paypal_url . "?" . $post_string);

            fclose( $fp );
        }

        if ( preg_match('/VERIFIED/i', $this->ipn_response ) ) {
            $this->log_ipn_results( true );
            return true;
        } else {
            $this->last_error = 'IPN Validation Failed.';
            $this->log_ipn_results( false );
            return false;
        }
    }

    function log_ipn_results( $success ) {
        if ( !$this->ipn_log )
            return;

        $text = '[' . date( 'm/d/Y g:i A' ) . '] - ';

        if ( $success )
            $text .= "SUCCESS!\n";
        else
            $text .= 'FAIL: ' . $this->last_error . "\n";

        $text .= "IPN POST Vars from Paypal:\n";
        foreach ( $this->ipn_data as $key => $value ) {
            $text .= "$key=$value, ";
        }

        $text .= "\nIPN Response from Paypal Server:\n " . $this->ipn_response;

        $fp = fopen( $this->ipn_log_file, 'a' );
        fwrite( $fp, $text . "\n\n" );

        fclose( $fp );
    }

}

当任何用户订购定期付款时，首次IPN会收到订阅注册和订阅付款，但第二天IPN无法接收。