Unable to create a subscription using /subscriptions endpoint

Question

Hi Team,

I have gone through the below documentation and trying to create subscription, but getting an error, please find the screenshots below:

https://learn.microsoft.com/en-us/graph/api/subscription-post-subscriptions?view=graph-rest-1.0&tabs=http

The notification URL used is publicly available.

Answer 1

@Mahesh Kurucheti

have you noticed notification URL validation as mentioned in here in your documentation ?

This error trends to occure due to lack of notification url validation..

when you create subscription, Microsoft graph validates your notification URL by sending some token such as this

POST https://{notificationUrl}?validationToken={opaqueTokenCreatedByMicrosoftGraph}

therefore, you need to separately handle that request from your notification endpoint.

in this scenario, take the value of validationToken and return it like below.

if (Request.QueryString["validationToken"] != null)
            {
                var token = Request.QueryString["validationToken"];
                return Content(token, "text/plain");
            }

make sure return content type "text/plan"

find this samples for more details

link

link2

link3

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