Events not showing in Post Notifications

Hi,
My site is set up to send out new post notifications via email using the MailPoet plugin. In these emails I have a section for upcoming events from your calendar plugin and this has worked just fine for a long time. Unfortunately this is no longer working.

I contacted the MailPoet people first, but they were unable to recreate the problem and asked me to reach out here to verify the following..

– The custom post type (event) has the ‘exclude_from_search’ => false
– The events are public and visible
– During which hook (it should be ‘init’) do they register your post type?`

I can verify that the events are indeed public, but I need help with the rest.

Thank you for any help in getting this resolved.