Blacklist email in Proofpoint
Sign into Proofpoint and choose the proper account. Either the dashboard will open with a list of customer accounts, or there will be a ‘house’ icon in the upper left. Click the house and the list of customer accounts will show.
In the left pane, under Security Settings click the Email drop down. Choose ‘Sender Lists’. In the main pane, ‘Blocked Sender List’ is the black list, and ‘Safe Sender List’ is the white list. Asterisks (*) count as a wildcard, so that *@somedomain.com means any sender from that domain.
Enter the email and domain in the appropriate list and click ‘Save’.