Azure event hub not sending events for existing shared mailbox
I am using Azure Event Hub to receive events related to emails.
I have created an azure app with required permissions to receive the events.
As a result I am able to successfully receive the events like message received, deleted.
Then I have created a Shared Mailbox, added existing users to that mailbox. Now I am able to receive the events from the shared mailbox as well.
The problem I am facing is that I am not able to received events from shared mailbox which previously exists before creating the Azure App. Same users are part of that mailbox as well.
However I am not receiving any events for those.
Could you please advise what I am doing wrong here? Or is this something expected?
Thanks