We have a .NET API Project that creates a subscription to group conversations changes (created/updated) and provides an endpoint for notifications to arrive to process the posts.
It has been working fine for about 2 years, until last Thursday (03/07) when it stopped working. On that day, we received the following error just once: invalid_grant Microsoft.Identity.Client.MsalUiRequiredException: Your app has been throttled by AAD due to too many requests
After that, we could keep creating subscriptions, but even though emails were coming to our group, no notifications on the API.
This is how we create the subscription: POST /subscriptions
After creating it, we successfully receive the POST request with the validation token, which we response 200 OK immediately.
For the record, we are using Delegated permissions with a work account, and that account has the required permissions (it was working until last week).
We would really appreciate your kind help!
We've tried creating a new App to see if it was because of some App lock, but no success.
We've tried changing the subscription Resource to be a user inbox, and it worked perfectly, being able to receive notifications each time a new email came to that particular user inbox. This was to verify if the issue was related to Office 365.
We've tried on my PC, using ngrok as public endpoint. Same behavior than the API sitting on our server. On my PC, we've also updated the Microsoft Graph package version from 4.48.0 to 5.44.0, but still same issues.