agent not connecting

The agent is not getting connecting. In the log agent-service.log I can see the below error.

Please help.

2016.07.18 12:14:20 459.844 SERVREQ: Error: Request POST to https://anturis.com/api/1/agent/authenticate failed (NetworkError: RemoteHostClosedError("Connection closed")) with QVariant(, )
2016.07.18 12:15:27 526.741 SERVREQ: Error: Request POST to https://anturis.com/api/1/agent/authenticate failed (NetworkError: RemoteHostClosedError("Connection closed")) with QVariant(, )
2016.07.18 12:18:00 680.221 SERVREQ: Error: Request POST to https://anturis.com/api/1/agent/authenticate failed (NetworkError: RemoteHostClosedError("Connection closed")) with QVariant(, )
2016.07.18 12:19:22 762.393 SERVREQ: Error: Request POST to https://anturis.com/api/1/agent/authenticate failed (NetworkError: RemoteHostClosedError("Connection closed")) with QVariant(, )