Hi Saroj Das,
The below is my screen,

The below is Error Log
Source : System
Method : GetRequestStream
Date : 03-12-2014
Time : 15:03:37
Error : The remote server returned an error: (504) Gateway Timeout.
Stack Trace : at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.ExecuteRegistrationRequest(String url, DeviceRegistrationRequest registrationRequest)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, LiveDevice device)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.LoadOrRegisterDevice(Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.GenerateDeviceCreds()
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.ValidateServerConnection(CrmOrgByServer selectedOrg)
======================================================================================================================
Source : System
Method : GetRequestStream
Date : 03-12-2014
Time : 15:03:57
Error : The remote server returned an error: (504) Gateway Timeout.
Stack Trace : at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.ExecuteRegistrationRequest(String url, DeviceRegistrationRequest registrationRequest)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, LiveDevice device)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.LoadOrRegisterDevice(Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.GenerateDeviceCreds()
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.ValidateServerConnection(CrmOrgByServer selectedOrg)
======================================================================================================================
Source : System
Method : GetRequestStream
Date : 03-12-2014
Time : 15:03:59
Error : The remote server returned an error: (504) Gateway Timeout.
Stack Trace : at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.ExecuteRegistrationRequest(String url, DeviceRegistrationRequest registrationRequest)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, LiveDevice device)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.LoadOrRegisterDevice(Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.GenerateDeviceCreds()
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.ValidateServerConnection(CrmOrgByServer selectedOrg)
======================================================================================================================
Source : System
Method : GetRequestStream
Date : 03-12-2014
Time : 16:32:00
Error : The remote server returned an error: (504) Gateway Timeout.
Stack Trace : at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.ExecuteRegistrationRequest(String url, DeviceRegistrationRequest registrationRequest)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, LiveDevice device)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.LoadOrRegisterDevice(Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.GenerateDeviceCreds()
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.ValidateServerConnection(CrmOrgByServer selectedOrg)
======================================================================================================================
Source : System
Method : GetRequestStream
Date : 03-12-2014
Time : 16:47:16
Error : The remote server returned an error: (504) Gateway Timeout.
Stack Trace : at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.ExecuteRegistrationRequest(String url, DeviceRegistrationRequest registrationRequest)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, LiveDevice device)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.LoadOrRegisterDevice(Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.GenerateDeviceCreds()
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.ValidateServerConnection(CrmOrgByServer selectedOrg)
======================================================================================================================
Source : System
Method : GetRequestStream
Date : 03-12-2014
Time : 17:08:56
Error : The remote server returned an error: (504) Gateway Timeout.
Stack Trace : at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.ExecuteRegistrationRequest(String url, DeviceRegistrationRequest registrationRequest)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, LiveDevice device)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.RegisterDevice(Guid applicationId, Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.Connector.DeviceIdManager.LoadOrRegisterDevice(Uri issuerUri, String deviceName, String devicePassword)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.GenerateDeviceCreds()
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.ValidateServerConnection(CrmOrgByServer selectedOrg)
======================================================================================================================