var result = authContext.AcquireTokenAsync(
                    authConfig.LoginResource,
                    authConfig.ClientId,
                    new UserPasswordCredential(authConfig.Username, authConfig.Password)
                ).Result;

var result = authContext.AcquireTokenAsync(
                    authConfig.LoginResource,
                    authConfig.ClientId,
                    new UserCredential(authConfig.Username)
                ).Result;