This particular plugin is built to block automated comment spam – any comment entered via the WP post/page comment form.
But I have other things that will block contact page form. Take a look at my FormSpammerTrap solution. It’s built as a standalone, but can be integrated with WordPress by creating a new template from your current theme’s page.php file. Full instructions on how to do that in the free code.
It’s all available at https://www.FormSpammerTrap.com . The process has been around for about 10 years, with improvements added all the time. Quite versatile, and quite effective. In all the years that I’ve had the FormSpammerTrap running on sites, I have never gotten any spambot contact form submissions.
And it is free. You can get it via the Contact form on the site (which is all done with the program, including automated sending of the files, the response, saving data, and more.)