fail2ban does not work with the seafile settings as found in the documentation. fail2ban jail does not get triggered. I can keep retrying the login beyond the 3 retries after seafile triggers captcha challenge and starts logging failures.
Perhaps the log format changed in seafile 7 as this regex statement seems incorrect:
failregex = Login attempt limit reached.*, ip: <HOST>
The actual line in the seafile 7 log looks like this:
[WARNING] seahub.auth.views:149 login Login attempt limit reached, show Captcha, email/username: admin, ip: 220.127.116.11, attemps: 5