No Callback Received After Creating Subscription for Change Notification

Question

We have created a subscription request for change notifications using Microsoft Graph API. However, after successfully creating the subscription, we are not receiving any callbacks to our specified notification URL when changes occur.

Could you please assist us in troubleshooting this issue? We have verified the following:

1. The subscription is created successfully, and we receive a valid subscription ID.
2. Our notification URL is reachable, and it is capable of handling POST requests.
3. There are relevant changes in the subscribed resource (e.g., a new email ).

Answer 1

Hello Commet Non Prod,

Thank you for reaching out to Microsoft Support!

It sounds like you've already taken some important steps to ensure your subscription is set up correctly. Since you have a valid subscription ID and your notification URL is reachable and capable of handling POST requests, let's delve into a few more areas that might help resolve the issue:

1. Validation Token: Ensure that your notification endpoint is correctly handling the validation token sent by Microsoft. When a subscription is created, Microsoft sends a validation request to your notification URL. Your endpoint must read the validation token from the query parameters and return it immediately. This step is crucial for the subscription to be validated successfully.
2. Response Status: Double-check that your notification endpoint is responding with a 200 OK status code to the validation request. If the endpoint does not respond with 200 OK, the subscription validation will fail.
3. Debugging Logs: Since your notification URL is reachable and can handle POST requests, ensure that you have proper logging in place to capture any incoming requests. This can help you identify if the validation request is reaching your endpoint and how it is being processed.
4. Firewall and Network Settings: Verify that there are no firewall or network settings blocking the validation request from Microsoft. Sometimes, network configurations can prevent external requests from reaching your endpoint.
5. Subscription Configuration: Review the subscription configuration to ensure all parameters are correctly set. This includes the resource type, change type, and expiration date. Any misconfiguration can lead to issues with receiving notifications.

Reference documents are as follows:

https://learn.microsoft.com/en-us/graph/change-notifications-overview

Hope this helps.

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