Able to create a Microsoft Graph subscription using ngrok but not with Azure url

Question

I'm doing this tutorial https://learn.microsoft.com/en-us/graph/tutorials/azure-functions, everything works fine when i use ngrok but if i replace ngrok value with my azure url app function, i get an error in the createdSubscription variable

var subscription = new Subscription
                {
                    ChangeType = "created",
                    NotificationUrl = $"{notificationHost}/api/Notify",
                    Resource = $"/users/{payload.UserId}/mailfolders/inbox/messages",
                    ExpirationDateTime = DateTimeOffset.UtcNow.AddHours(5),
                    ClientState = Notify.ClientState
                };

                // POST /subscriptions
                var createdSubscription = await graphClient.Subscriptions
                    .Request()
                    .AddAsync(subscription);

saying this System.NullReferenceException: 'Object reference not set to an instance of an object.', as i said before if i use ngrok everything works but if i use my azure url, no

(1) share the detailed error response that you receive along with timestamp, requestid (2) Test the above outside of code and see still you can repro the issue in POSTMAN/Graph explorer as well — Dev, Aug 12 '21 at 18:48

score 0 · Answer 1 · answered Aug 30 '21 at 11:55

The message "Object not set to an instance of Object" means you are trying to use an object which has not been initialized. This boils down to one of these:

Your code declared an object variable, but it did not initialize it (create an instance or 'instantiate' it)
Something which your code assumed would initialize an object, did not
Possibly, other code prematurely invalidated an object still in use

Check the SO for detailed information.

Able to create a Microsoft Graph subscription using ngrok but not with Azure url

1 Answers1