public override  Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
    {
        AccountLogin LogCredentials = new AccountLogin();
        LogCredentials.UserName = context.UserName;
        LogCredentials.Password = context.Password;
        LogCredentials.IPAddress = "::1";

        string webHost = Convert.ToString(WebConfigurationManager.AppSettings["webHost"]);
        context.OwinContext.Response.Headers.Add("Access-Control-Allow-Origin", new[] { webHost });

        ProviderLoginResponse providerLoginResponse = MembershipService.UserLogin(LogCredentials);
        if (providerLoginResponse.LoginStatus != "Y")
        {
            context.SetError("invalid_grant", "The user name or password is incorrect.");
            return Task.FromResult<object>(null);
        }

        var claims = new List<Claim>()
            {
                    new Claim(ClaimTypes.Sid, Convert.ToString(providerLoginResponse.UserID)),
                    new Claim(ClaimTypes.Name, providerLoginResponse.UserName),
                    new Claim(ClaimTypes.Email, providerLoginResponse.UserEmail)
            };

        ClaimsIdentity oAuthIdentity = new ClaimsIdentity(claims,
                    Startup.OAuthOptions.AuthenticationType);

        AuthenticationProperties properties = CreateProperties(providerLoginResponse);

        AuthenticationTicket ticket = new AuthenticationTicket(oAuthIdentity, properties);
        context.Validated(ticket);
        return Task.FromResult<object>(null);
    }

[HttpGet]`
[Route("GetColumn")]
public HttpResponseMessage GetColumn(HttpRequestMessage request)
{
    string tableName = "";
    HttpResponseMessage response = null;
    try
    {
       var clientList = _settingsService.GetColumns(tableName);
       response = request.CreateResponse(HttpStatusCode.OK, new APIResponse { Status = true, Data = clientList, Message = Messages.Saved_Success });
    }
    catch (Exception ex)
    {
        response = request.CreateResponse(HttpStatusCode.OK, new APIResponse { Status = false, Data = null, Message = ex.Message });
    }
    return response;
}`

function GetColumn(data, cb) {
        var token = sessionStorage.getItem('accessToken');

        var headers = {};
        if (token) {
            headers.Authorization = 'Bearer ' + token;
        }

        $.ajax({
            type: 'GET',
            url:  "api/Settings/GetColumn",
            headers: headers
        }).done(function (data) {
            cb(data);
        }).fail(function (Res) {
            cb(Res);
        });
    };