Sometimes getting error 502 "Unexpected EOF at target"

[#1]

trace.ziptrace.zipHi Apigee Community,

We have installed Apigee Edge for Private Cloud Version 4.16.09.00.

In one of our proxies we noticed error response:

{"fault":{"faultstring":"Unexpected EOF at target","detail":{"errorcode":"messaging.adaptors.http.flow.UnexpectedEOFAtTarget"}}}

with status code 502 returned when sending requests to this proxy.

Most of the time developers using this proxy are receiving correct responses, this error is returned only for some of the requests send.

We thought that it might be connected to target server configuration described here: https://community.apigee.com/questions/8894/target-server-for-secure-connection-throws-502-err.html.

However performing http GET on this target server returned:

{
  "host": "foo.bar.com",
  "isEnabled": true,
  "name": "MyServerName_server",
  "port": 443,
  "sSLInfo": {
    "ciphers": [],
    "clientAuthEnabled": "false",
    "enabled": "true",
    "ignoreValidationErrors": false,
    "protocols": []
  }
}

I am attaching trace.zip with captured example error response.

Do you have any ideas what might be causing this issue? Could you help us to solve it?