[Solved] User logins/hour excessive causing Fail2Ban blocks

[darond]

Thanks @JoshData

I have found this from 2015

fail2ban is angry - researching cause

Hey All, I noticed the other day my mail-in-a-box server was running slow. After some research, I found that the fail2ban service was running wild with processor time (97%). Stopping the service seems to resolve the issue completely, but obviously that is not ideal. Usage metrics seem to indicate this started about a week ago. Nothing was changed at that time that I am aware of. Looking in the fail2ban logs really shows nothing interesting at all. The auth.log showed the normal batch of p…

which is exactly the same issue (at least the entries in mail.log are the same) and had similar implications with fail2ban blocking. The user indicated it might be related to ActiveSynce / z-push so will look at that.