HubSpot allows you to block email addresses belong to specific domains from submitting forms. This helps cut down on spam.
Occasionally, a spammer will repeatedly attempt contacting you via form on your website. Assuming they are using the same email address or the same email domain each time, there is an easy way to block them from submitting future forms. Watch this video for the instructions:
For additional information, read this article on HubSpot's knowledge base: Block form or pop-up form submissions from specific email domains.