When there is an error booking an event due to an external calendar error (e.g. 404 Google Calendar not found), the email gets sent, but the event gets rolled back and deleted.
Here's how it happened:
1. CozyCal was connected to your Google Calendar, with it syncing to "Calendar ABC" (as an example).
2. Access to "Calendar ABC" was removed (or it was deleted) from your Google Account
3. When a guest tried to book, the email was sent, however an error occurred adding it to your external calendar since CozyCal no longer has access to "Calendar ABC".
4. Because of this error, we did a "rollback" so that the event was deleted.
5. An error was shown to your guest saying "Network error occurred"
[ ] Handle GCal 404 errors: automatically reset the calendars
[ ] Think about how to handle external calendar errors globally. Maybe they shouldn't be rolled back.