HTTP ERROR 504

HTTP ERROR 504

Problem accessing ZCS upstream server. Reason: Cannot connect to the ZCS upstream server. Connection timeout.
Possible reasons:

• upstream server is blocked by a firewall
• upstream server is failing to send back the response in time
• upstream server is down

Please contact your ZCS administrator to fix the problem.
Powered by Nginx-Zimbra://

cara mengatasinya restart proxynya dengan  perintah :
# su - zimbra


$ zmtlsctl both


$ zmcontrol stop && zmcontrol start