If you wish to add a user to your Blacklist in your Mailbox then please follow this guide.
1: In OX Webmail , click on the Hamburger Menu in the top left hand corner of the screen.
2: Following the drop downs, press Settings .
3: Ensure E-mail is selected and on the right hand pane, scroll down to Access Lists, ensure Blocklist is selected and select Add new address .
4: Here you can enter a new mail address for you to add to your Blocklist , make sure you press Add .
5: As you can see, the mail address has been successfully added to your Blocklist.
6. Congratulations! You have now successfully added a mail address to your Blocklist !