I would like to request if you can help me block someone’semail address

and block all incoming emails from him/ her.

Admin -> Postmaster filter. Please read the documentation first! Try to work it out yourself, if that really doesn't work, give a precise description of the problem (what do you want, what OTRS doesn't do what you did expected it to do and what OTRS did do). Then people may be able (and willing) to help. Posting every little hickup to mailinglist won't help you, try for yourself (put some effort in it!) first. Regards, Richard