0
無法連接到端口號爲2196的feedback.sandbox.push.apple.com。 打開端口（5223，2915，2916，443 ）在Windows防火牆與TCP/SSL。無法通過pushsharp中的tcp客戶端連接到feedback.sandbox.apple.com
試圖通過telnet連接，但沒有幫助。
獲取以下例外
Service Exception: PushSharp.Apple.ApplePushService -> System.Net.Sockets.Socket
Exception (0x80004005): A connection attempt failed because the connected party
did not properly respond after a period of`enter code here` time, or established connection faile
d because connected host has failed to respond 17.172.232.45:2196
at System.Net.Sockets.TcpClient..ctor(String hostname, Int32 port)
at PushSharp.Apple.FeedbackService.Run(ApplePushChannelSettings settings, Can
cellationToken cancelToken) in d:\Sample Apps\Push Notification\PushSharp-master
\PushSharp-master\PushSharp.Apple\FeedbackService.cs:line 60
at PushSharp.Apple.ApplePushService.<>c__DisplayClass4.<.ctor>b__1(Object sta
te) in d:\Sample Apps\Push Notification\PushSharp-master\PushSharp-master\PushSh
arp.Apple\ApplePushService.cs:line 51
Failure: PushSharp.Apple.ApplePushService -> The maximum number of Send attempts
to send the notification was reached! -> {"aps":{"alert":"Hello World!","badge"
:7,"sound":"sound.caf"}}
而且，這並不需要證書來連接到沙箱，那麼爲什麼這一例外？