Check whether it is connected via the iCloud option or not. If you connected it through the iCloud option and want to import flights, connect it through the IMAP option in the app settings.
This allows us to import flights from your iCloud email. In the Host field, enter imap.mail.me.com.
Note: Please make sure you only enter the username. This is typically the named part of the iCloud email address (e.g., emilyparker, not firstname.lastname@example.org). If your email client cannot connect to iCloud using only the named part of the iCloud email address, try using the full address.
If you connected it via the IMAP option and still don't see flights, check this article.