Error - {"message": "Network error communicating with endpoint"}

That error usually means your client never actually reached the API endpoint — the request failed at the network layer before any response was returned. A few common causes in your code:

Issues in Your Code

1. Missing scheme (https://)
   You wrote:

   new RestClient("api.nimbuspost.com/v1/courier/serviceability");
   

   This is not a valid URL. It should be:

   new RestClient("https://api.nimbuspost.com/v1/courier/serviceability");
   

2. Authentication
   NimbusPost’s API requires an API key / token in the headers. Without it, the server may reject the request. Example:

   request.AddHeader("Authorization", "Bearer YOUR_API_KEY");
   

3. Timeout
   Setting client.Timeout = -1; disables timeout. If the server is unreachable, your call may hang or throw a network error. Use a reasonable timeout (e.g., 30 seconds).

4. Content-Type header
   For a GET request, Content-Type: application/json is not necessary. It’s usually used for POST/PUT with a body. Some APIs may even reject it.

Corrected Example

var client = new RestClient("https://api.nimbuspost.com/v1/courier/serviceability");
client.Timeout = 30000; // 30 seconds

var request = new RestRequest(Method.GET);
request.AddHeader("Authorization", "Bearer YOUR_API_KEY"); // required
// request.AddHeader("Content-Type", "application/json"); // not needed for GET

IRestResponse response = client.Execute(request);

if (response.IsSuccessful)
{
    Console.WriteLine(response.Content);
}
else
{
    Console.WriteLine($"Error: {response.StatusCode} - {response.ErrorMessage}");
}

Checklist

• Use full URL with https://

• Add required Authorization header

• Set a proper timeout

• Remove unnecessary headers for GET

Hi Ramco

First, try a curl request to your backend integration endpoint using the same parameters that you expect API Gateway to pass. Confirm that the request completes and takes less than 29 seconds, which is the API Gateway timeout.

Next, try calling your API via the test facility in the API Gateway console and inspect the output to get more information. Confirm that API Gateway is calling the correct endpoint and is passing the header and body values that you expect. Also, observe any error messages from calling the integration endpoint.

If that doesn't help, then enable CloudWatch logs on your deployed API, make a few test requests, and inspect the resulting logs.

If you're still unable to figure it out, you can post the output from the previously mentioned steps along with a swagger export of your API. If any of these contain sensitive information, you can PM them to me instead.