This operation is logically possible if you have deployed a unique certificate for each user. This feature is available with Artica v4.50 Service pack 1 or Artica v4.50 with HotFix 20231112-20
On the left menu, choose Web services > Client Certificates
Click on the Ban Clients button
To ban a client certificate, click on New rule button
Select the website affected by the rule, if no site is selected, then all websites will be affected
Give the name that will be matched inside the certificate data after the CN= also known as “Common Name” ( regular expression can be used )