Failed to send messages to FCM.

Bắt đầu với Java server-side sample và kiểm tra Messaging.java tại getAccessToken (dòng 50), getConnection (dòng 68), sendMessage (dòng 83) và sendCommonMessage (dòng 191). Tái hiện sample bằng project_id được báo cáo và theo dõi yêu cầu token kết thúc bằng Connection reset. Công việc được xem là hoàn tất khi xác định được nguyên nhân và ghi lại một cách giải quyết đã được xác minh.

  I  use the  java server side sample then change the my  `project_id` variable in `com.google.firebase.quickstart.Messaging.java' . The following logs show in my project. I  don't know why.

java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:210)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at sun.security.ssl.InputRecord.readFully(InputRecord.java:465)
at sun.security.ssl.InputRecord.read(InputRecord.java:503)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:973)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1375)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1403)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1387)
at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream0(HttpURLConnection.java:1316)
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1291)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:250)
at com.google.api.client.http.javanet.NetHttpRequest.execute(NetHttpRequest.java:77)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:981)
at com.google.api.client.auth.oauth2.TokenRequest.executeUnparsed(TokenRequest.java:283)
at com.google.api.client.auth.oauth2.TokenRequest.execute(TokenRequest.java:307)
at com.google.api.client.googleapis.auth.oauth2.GoogleCredential.executeRefreshToken(GoogleCredential.java:384)
at com.google.api.client.auth.oauth2.Credential.refreshToken(Credential.java:489)
at jp.co.kyocera.thp.sendNotice.service.Messaging.getAccessToken(Messaging.java:50)
at jp.co.kyocera.thp.sendNotice.service.Messaging.getConnection(Messaging.java:68)
at jp.co.kyocera.thp.sendNotice.service.Messaging.sendMessage(Messaging.java:83)
at jp.co.kyocera.thp.sendNotice.service.Messaging.sendCommonMessage(Messaging.java:191)