Value of resource when subscribing to webhook notifications using graph api - sharepoint

Question

I am trying to subscribe to the Microsoft Graph API for webhook notifications to track changes in a folder in a SharePoint Document library. I have app only access to this SharePoint site and am able to see and download all the content within the drive associate with the document library. I can also upload new files using API.
When I make the call to the subscription endpoint I receive an internal server error.
Here is the request I make
curl -X POST \
https://graph.microsoft.com/v1.0/drive/root/subscriptions \
-H 'Accept: */*' \
-H 'Accept-Encoding: gzip, deflate' \
-H 'Authorization: Bearer TOKEN' \
-H 'Cache-Control: no-cache' \
-H 'Connection: keep-alive' \
-H 'Content-Length: 303' \
-H 'Content-Type: application/json' \
-H 'Host: graph.microsoft.com' \
-d '{
"changeType": "updated",
"notificationUrl": "https://c.ngrok.io/sp-hook",
"resource": "drives/{{DRIVE-ID}}/root",
"expirationDateTime": "2019-09-18T11:23:00.000",
"clientState": "test"
}'
Here is the response I get
{
"error": {
"code": "InternalServerError",
"message": "Unable to find target address",
"innerError": {
"request-id": "c8e66e50-5b94-4593-88d5-3111e5c5c6c7",
"date": "2019-09-13T09:50:12"
}
}
}
I believe this could be due to a wrong resource value, but I could not locate documentation about what the value of resource should be. I have gone over: https://learn.microsoft.com/en-us/graph/webhooks and https://learn.microsoft.com/en-us/graph/api/resources/webhooks?view=graph-rest-1.0. All the documentation seems to point to a resource value of "me/drives/root", however with app only access a my site is not defined and so the call fails.
These are the different values for resource that I have tried within the request json body
drives('DRIVE-ID')/root
drives/DRIVE-ID/root
DRIVE-ID
drive/DRIVE-ID
drive/DRIVE-ID/root
me/drive("DRIVE-ID")/root
DRIVE-ITEM-ID-FOR-ROOT
Different documentation seems to point to different subscription endpoints. These are the different endpoints I have tried
https://graph.microsoft.com/v1.0/subscriptions
https://graph.microsoft.com/v1.0/drive/root/subscriptions
https://graph.microsoft.com/beta/drives/{{drive-id}}/root/subscriptions
The error also made me suspect that during subscription registration, it was not able to find my webhook. However having tested the endpoint I am sure it is accessible.
Additional information
I use the following call to get the drive id for a sharepoint site
curl -X GET \
'https://graph.microsoft.com/v1.0/sites/SITE-ID/drive' \
-H 'Accept: */*' \
-H 'Accept-Encoding: gzip, deflate' \
-H 'Authorization: Bearer TOKEN' \
-H 'Cache-Control: no-cache' \
-H 'Connection: keep-alive' \
-H 'Content-Type: application/json' \
-H 'Host: graph.microsoft.com' \

Answer 1

I see you are performing POST on https://graph.microsoft.com/v1.0/drive/root/subscriptions endpoint
Expected subscriptions endpoint is https://graph.microsoft.com/v1.0/subscriptions
Please note there is no '/drive/root' in the URL path.