Note: As of 20 February 2020 this should no longer be an issue. Additional email headers are sent and certificates installed on the server that should allow all emails to make it through spam filters.
Skippers with an Apple email address (e.g. @me.com, @icloud.com) may have their emails sent from Crew Manager go to a spam folder. Crew members will need to add the Skipper's Apple address to a "white list" so it is not flagged as spam. A better work around is to get a free Gmail account and use that with Crew Manager. You may setup Gmail to automatically forward to your Apple email address so you don't need to check a separate email account.