Connecting to localhost using HttpClient in C#

When getting error message:

The SSL connection could not be established, see inner exception.

Inner exception:

The remote certificate is invalid according to the validation procedure.

We need to add a client handler that will simply accept all certificates no matter what.

private static async Task<HttpResponseMessage> Request(object request, string url, string headerKey, string secret)
{
    using (var httpClientHandler = new HttpClientHandler())
    {
        // Return `true` to allow certificates that are untrusted/invalid
        httpClientHandler.ServerCertificateCustomValidationCallback =
            HttpClientHandler.DangerousAcceptAnyServerCertificateValidator;

        using (var client = new HttpClient(httpClientHandler))
        {
            client.DefaultRequestHeaders.Add(headerKey, secret);

            var reqJson = JsonConvert.SerializeObject(request);
            var content = new StringContent(reqJson, Encoding.UTF8, "application/json");
            var response = await client.PostAsync(url, content);

            return response;
        }
    }
}