I am trying to send POST request from a NodeJs script to Python server (running with flask and waitress).
Most of the times the request is failed with the below error.

(node:42790) UnhandledPromiseRejectionWarning: Error: socket hang up
    at connResetException (internal/errors.js:639:14)
    at TLSSocket.socketOnEnd (_http_client.js:499:23)
    at TLSSocket.emit (events.js:412:35)
    at endReadableNT (internal/streams/readable.js:1334:12)
    at processTicksAndRejections (internal/process/task_queues.js:82:21)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:42790) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2)
(node:42790) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

I am using NodeJs with axios package to send the request, and the configuration is as given below:

    let axiosClient = axios.create({
      timeOut: 300000,
      maxContentLength: Infinity,
      maxBodyLength: Infinity,
      httpsAgent: new https.Agent({ keepAlive: true }),
      httpAgent: new http.Agent({ keepAlive: true }),
    });

    let response = await axiosClient.post(end_point_url, data);

And when I checked in the server I could see that the 200 response is being sent, however in the client it is throwing an error.

My expectation is it should be successful in the first try, hence catching the error and retrying may not help in my case as most of the times it fails anyways.

Could you please guide in finding the root cause and fixing the same.

Thank you