Many hackers and spammer have habit of harming website at regular interval and if you dont take appropriate measure they keep on harming your website by different means

There are many reasons that make you to block certain users from yours Email list , and it is also necessary to block those emailers who are sending you spam at regular intervals , Hackers are sending virus and harmfuls codes to hack emails account througn mails.so it is always recommended to block all those emails using Filters on Emails