User Information or send mail with Graph API httpclient.SendAsync error

I am trying to build my first Graph API app. I have a console app and have registered the app in Azure AD.

Steps i followed till now

In Azure

1) After registering the app i can get the Application ID ( client ID ) and added a key so key value as ( client secret). 

2) Added a test user with global admin role to AD 

3) Added the same user to Owners

4) under Required Permission added graph api with Read /write access to user and mails ( Application and delegate permissions ) 

Console App 

1) Called a get access token function 

2) Then used the token with http client to make a request to graph url 

 public static string GetAccessToken()
        {
            // Step: Get the access token
            // Create the authentication context (ADAL)            
            var authenticationContext = new AuthenticationContext(Authority);

            // Get the access token
            //KJ
            //var authenticationResult = authenticationContext.AcquireToken(GraphResource,
            //    ClientId, RedirectUri, PromptBehavior.RefreshSession);
            ClientCredential clientCred = new ClientCredential(AppModeConstants.ClientId,
                   AppModeConstants.ClientSecret);
            //var authenticationResult = authenticationContext.AcquireTokenAsync(GraphResource, ClientId, RedirectUri, new PlatformParameters(0)).Result.AccessToken;
            var authenticationResult = authenticationContext.AcquireTokenAsync(GraphResource, clientCred).Result.AccessToken;
            var accessToken = authenticationResult;

            return accessToken;
        }



public static async Task<string> GetMyEmailAddress()
        {
            string accessToken = Model.MailClient.GetAccessToken();
            // Get the current user. 
            // The app only needs the user's email address, so select the mail and userPrincipalName properties.
            // If the mail property isn't defined, userPrincipalName should map to the email for all account types. 
            string endpoint = "https://graph.microsoft.com/v1.0/me";
            string queryParameter = "?$select=mail,userPrincipalName";
            UserInfo me = new UserInfo();
            
            using (var client = new HttpClient())
            {
                using (var request = new HttpRequestMessage(HttpMethod.Get, endpoint + queryParameter))
                {
                    request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                    request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);

                    // This header has been added to identify our sample in the Microsoft Graph service. If extracting this code for your project please remove.
                    //request.Headers.Add("SampleID", "aspnet-connect-rest-sample");

                    using (var response = await client.SendAsync(request))
                    {
                        if (response.IsSuccessStatusCode)
                        {
                            var json = JObject.Parse(await response.Content.ReadAsStringAsync());
                            //me.Address = !string.IsNullOrEmpty(json.GetValue("mail").ToString()) ? json.GetValue("mail").ToString() : json.GetValue("userPrincipalName").ToString();
                        }
                        //return me.Address?.Trim();
                        return "temp";
                    }
                }
            }
        }

But i get no response back as i execute 

client.SendAsync(request)

I also tried with other url but to no use, Can someone help with this.

Thanks,

KJ