I have 2 .net core 2.2 applications running in Kubernetes cluster. The services use HttpClient.SendAsync to communicate with one another through Kubernetes services. The applications work well on bare-metals. However, the communication with HttpClient throws No such device or address exception. Here is one of the URLs used: http://svc-biz4xbackend:5002/api/v1/Identity/SessionValidate. I kubectl exec into the pod and curl the url and it works fine. Does this indicate that this could be a bug with .Net Core framework? Where should I start to debug?

        private async Task<HttpResponseMessage> Send(HttpMethod method, string url, HttpContent content, CancellationToken cancel, TimeSpan timeout = default)
        {
            try {
                var client = _client;
                if (timeout != default)
                    client.Timeout = timeout;
                Uri uri = new Uri($"{client.BaseAddress}{url}", UriKind.Absolute);
                using (var httpRequestMessage = new HttpRequestMessage(method, uri))
                {
                    if ((method == HttpMethod.Post || method == HttpMethod.Put) && content != null)
                        httpRequestMessage.Content = content;//new StringContent(JsonConvert.SerializeObject(postData), _encoding, "application/json");
                    httpRequestMessage.Headers.Add("X-User-Id", new List<string>() {_authzContext.UserId});
                    httpRequestMessage.Headers.Add("X-Session-Id", new List<string>() {_authzContext.SessionId});
                    return await client.SendAsync(httpRequestMessage, cancel);
                }
            } catch (Exception e) {
                _logger.LogCritical($"Client.{nameof(Send)} url: {_client.BaseAddress}{url} Exception! {e.Message} {e.GetInnerMessage()} {e.StackTrace}");
                return null;
            }
        }