blocking TLD with regex won't work even though reported as denied.

Hi, I'm trying to block a certain TLD (.co) on cpanel using a regex match. I've setup a following global email filter using from with regex matches rule: @.*\.co$
And I've tested the filter and reported working Sub-condition is false: not first_delivery Condition is false: not first_delivery and error_message Match expanded arguments: Subject = test@localhost.co Pattern = @.*\.co$ Condition is true: $header_from: matches @.*\\.co\$ Condition is false: error_message Return-path copied from sender Sender = ourdomain@email.server.com Recipient = ourdomain@email.server.com Testing Exim filter file "/etc/vfilters/ourdomain.com" Headers charset "UTF-8" Fail text "REJECT" Filtering ended by "fail".
But still being accepted by our email regardless of the email rule. Any thoughts or am I doing something wrong?