Object reference not set to an instance of an object

[thomps0]

Where did you get the code?

• Downloaded from GitHub
• Downloaded from the Microsoft Graph quick start tool
• Followed the tutorial from Microsoft Graph tutorials

Describe the bug
I've tried both following the tutorial, as well as downloading from GitHub and have what I believe is the same error that the other user posted. Currently can pull new messages, but on subscribing an email address I'm left with an "Object reference not set to an instance of an object" error. It fails out on azurefunctions.js:59 and does so every time.

Error on the web page is: Call to SetSubscription returned 500 "Internal Server Error"

Error in the console is:
[2021-05-14T17:28:38.394Z] Executed 'Notify' (Succeeded, Id=6a4ec2e3-f68e-4a4e-aa28-431bcb4f75a5, Duration=4ms)
[2021-05-14T17:28:39.069Z] Executed 'SetSubscription' (Failed, Id=13cfe347-1cde-4e97-80b8-011ab221e9fc, Duration=1801ms)
[2021-05-14T17:28:39.071Z] System.Private.CoreLib: Exception while executing function: SetSubscription. Microsoft.Graph.Core: Object reference not set to an instance of an object.

To Reproduce
Steps to reproduce the behavior:

1. Go to Subscriptions
2. Enter an email address
3. Click Subscribe
4. See error

Expected behavior
Should subscribe the email.

Screenshots
N/A

Desktop (please complete the following information):

• OS: Windows 10
• Browser Chrome, Firefox and Edge (happens in all browsers)
• Version [e.g. 22]

Dependency versions

• Authentication library (MSAL, etc.) version:
• Graph library (Graph SDK, REST library, etc.) version:

Additional context
Function Runtime Version: 3.0.15417.0
.NET SDK 5.0.202 (x64)
Running this from PowerShell using Azure Command Line
Editor: Visual Studio Code

[jasonjoh]

Thanks for the added detail @thomps0! Since you're using Visual Studio Code, could you set a breakpoint on SetSubscription and see exactly which line of code the error is coming from? It will explicitly return a 500 if it doesn't find the webHookId, webHookSecret, tenantId, or apiFunctionId config values. However, it looks like from your output that Microsoft.Graph.Core is the one throwing the error.

The other things to verify are:

• The email address you are entering matches the user's userPrincipalName. This isn't always the case, so it's worth verifying.
• The user's mailbox is hosted on Exchange Online.

[thomps0]

Thanks for replying @jasonjoh.

• I have confirmed that the email = UPN (cloud only user in a dev tenant with E5 licensing)

• The user's mailbox is hosted in EOL.

The error occurs on azurefunctions.js:59 and does so every time an address is present. If I leave the input blank, the code handles the error and tells me to input an email address.

I also get 200 replies for the Notify service (screenshot attached)

This is the error in the Azure function:

I can also confirm that I am able to connect to the Tenant/App and pull new messages:

The only piece that seems to be breaking is when I go to create a subscription. Let me know if you need any more details, but the code base is identical to what is hosted on GitHub so I'm going a little crazy here - also knowing this is probably a simple mistake staring me in the face.

[jasonjoh]

Well the error in azurefunctions.js is because the Azure Function is encountering an error. We need to figure out why. Can you put a breakpoint on the Run function in SetSubscription.cs and step through the repro?

[thomps0]

Thanks for the patience Jason, I actually had to run it in Visual Studio because the debugger in VSCode wouldn't launch. I stepped through and didn't see anything that stood out as Null that shouldn't have been. It fails out on this section of code in the SetSubscription.cs file (screenshot below). It picks up the webHookID, webHookSecret, tenantID, apiFunctionID and even finds my username.

Not really sure what else to poke around in but if you want to see more screenshots just let me know.

[jasonjoh]

What does subscription look like prior to the call? Also, what version of Microsoft.Graph are you using?

[thomps0]

Subscription values can be seen above in the screenshot.

Graph version is 3.8.0 and I've included all the dependent packages:

[jasonjoh]

Could you update Microsoft.Graph to latest release version 3.32.0 and retry? There was a bug in the SDK around subscriptions and invalid tokens: microsoftgraph/msgraph-sdk-dotnet-core#145

[thomps0]

OK so I've updated to 3.32.0 and got a couple build errors I can't seem to work through (probably due to my lack of understanding of what everything is doing):

Those are the two build errors now, and here are the referenced code blocks (both in Notify.cs):