There was an issue sending the notification message to the Google Cloud Messaging (GCM) server. 3 attempts to re-establish the connection have failed, so the notification message cannot be sent. You can test network connectivity including firewall settings by trying https://android.googleapis.com/gcm/send in a web browser on this server. Exception Thrown: javax.net.ssl.SSLHandshakeException: Remote host closed connection
openssl s_client -connect android.googleapis.com:443
lynx https://android.googleapis.com/gcm/send