The way you quickly train the spam filter (and get your own personal Bayes database) with Fastmail is to set up two folders, specifically designed to facilitate identification of spam and ham. Once setup correctly, those folders are scanned daily for new messages. Once 200 spam and 200 ham messages have been used to train your Bayes database, that is used in place of the global Bayes. For details, read
https://www.fastmail.help/hc/en-us/a...pam-protection
Note that it is most effective if you can use messages that you know were mischaracterised in the past.