Updating user profile via REST (C#) yields "Forbidden"

Summary: trying to update the user profile using POST REST call yields “Forbidden”.

Details:

I have the following code. id is the ID of the user.

FetchUser is another method that calls ListUsers with the ID so that only that user’s profile is returned.

I set a breakpoint at the last line to see what result I’m getting. It is always “Forbidden.” I can do this same update in Postman with no problems, so I know it’s something with my code.

Any ideas what I’m doing wrong?

public IActionResult UpdateUser(string id, string firstName, string lastName)
{
  UserProfile userProfile;

  FetchUser(id, out userProfile);
  userProfile.FirstName = firstName;
  userProfile.LastName = lastName;

  HttpClient client = new HttpClient();
  client.BaseAddress = new Uri(Startup.Configuration["Okta:Domain"]);
  client.DefaultRequestHeaders.Clear();
  client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

  var PostTask = client.PostAsJsonAsync("/api/v1/users/" + id, userProfile);
  PostTask.Wait();

  HttpStatusCode code = PostTask.Result.StatusCode;
  AdminModel model = new AdminModel();
  CopyUserProfileToModel(userProfile, model);

  return View(model);
}

Please disregard. I found the method in the SDK that corresponds to what I am trying to do:

    var PostTask = _usersClient.UpdateUserAsync(theUser, theUser.Profile.Login, default(System.Threading.CancellationToken));
    PostTask.Wait();