What need users to put in the whitelist of their mailbox to prevent WP generated mails to end up in spam?
Say the server use something like that:
wp_mail( 'firstname.lastname@example.org', 'The subject', 'The message', 'From: My Name <email@example.com>' );
Is it working if users just put 'firstname.lastname@example.org' in the whitelist? Or what should they use?