Subscription validation request failed. Must respond with 200 OK to this request.

[gantonioid]

I'm trying to create a Graph Outlook webhook calling an azure function whenever a new email arrives to my inbox.

Expected behavior

So I would expect a "Subscribed successfully" message or similar. So the new emails trigger my Azure Function

Actual behavior

Subscription validation request failed. Must respond with 200 OK to this request.

Steps to reproduce the behavior

With my Microsoft Account, uing the graph-explorer.
[POST] to https://graph.microsoft.com/v1.0/subscriptions
{
"changeType": "created,updated",
"notificationUrl": "https://fridahook.azurewebsites.net/api/Subscriber",
"resource": "me/mailFolders('Inbox')/messages",
"expirationDateTime":"2019-10-01T18:23:45.9356913Z",
"clientState": "secretClientValue"
}

HTTP traffic capture

Here's the error

[gantonioid]

My request-id "40aeebdb-99cc-4fbc-9f55-187ad9266427" (so anyone can copy+paste it)

[MIchaelMainer]

This question is not about Graph Explorer.

Azure Functions are not the best option for this scenario. Please consider another option for your listener.

[gantonioid]

My case is based on this article Microsoft Graph bindings for Azure Functions that claims such scenario is valid.

Anyhow, the response you're referencing is for a timeout error, this is different. Could someone look into it?

[MIchaelMainer]

Is your Azure Function at https://fridahook.azurewebsites.net/api/Subscriber responding with a 200?

[MIchaelMainer]

Would you mind posting your question on StackOverflow so that the community can see it? Then post the URL in this issue.

[gantonioid]

Is your Azure Function at https://fridahook.azurewebsites.net/api/Subscriber responding with a 200?

The response of my function is the same Subscription validation request failed. Must respond with 200 OK to this request. Therefore I assume it has something to do with Graph, rather than the azure function.

Here's the link to my question on StackOverflow