503 Service Unavailable(Intermittent issue) when calling Backend Webservice from Apigee On-Cloud

[mathanprasathk]

Hi Team,

I'm calling a Backend Webservice through it's NATed IP address from Apigee Edge On-Cloud variant and only one or two request is successful and 99% of the request to Backend is failing with the below error. Could you please help me on this?

Error:

HTTP/1.1 503 Service Unavailable

Date:

Thu, 15 Dec 2016 13:02:19 GMT

Content-Length:

279

Connection:

keep-alive

Content-Type:

application/json

Server:

Apigee Router

{

"Envelope": {

"encodingStyle": "http://schemas.xmlsoap.org/soap/encoding/",

"Body": {

"Fault": {

"faultcode": "soap:Server",

"faultstring": "The Service is temporarily unavailable",

"faultactor": {},

"detail": {

"source": {

"errorcode": "messaging.adaptors.http.flow.ServiceUnavailable"

}

}

}

}

}

}

The NATed IP I'm calling is Http and my HTTPTargetConnection is below. I appreciate your quick response.

<HTTPTargetConnection>

<URL>http://[HostIP]:[PortNum]/Implementation/WebServiceGateway/WebServiceGatewayEndpoint</URL>

</HTTPTargetConnection>

Many thanks.