android - gcm 服务器获取 HTTP 状态 500 - 6 次尝试后无法发送消息

Question

我已经在 gcm_demo 页面上成功注册了我的设备，消息类似于“1 个设备已注册！”。

但是当我点击页面上的发送消息时，它最终变成了这样：

HTTP Status 500 - Could not send message after 6 attempts
type Exception report
message Could not send message after 6 attempts
description The server encountered an internal error that prevented it from fulfilling this request.

例外

java.io.IOException: Could not send message after 6 attempts
    com.google.android.gcm.server.Sender.send(Sender.java:136)
    com.google.android.gcm.demo.server.SendAllMessagesServlet.doPost(SendAllMessagesServlet.java:83)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)