ArgumentException occurs in pushSharp.

private static PushSharp.Apple.ApplePushChannelSettingsAppleSettings=null;
private static PushSharp.Apple.ApplePushChannelSettingsGetAppleSettingsDebug()
{
    if(appleSettings==null)
    {
        // TODO:configuration settings
        varAppleCert=File.ReadAllBytes(@"D:\APNs\development.p12");
        AppleSettings=new PushSharp.Apple.ApplePushChannelSettings(appleCert, "xxxxxx";
    }
    return appleSettings;
}