Hack tool, please contact support – WordPress

I came across an error recently that users were getting when trying to login to book events on a wordpress site. The error was:

“Hack tool, please contact support”

That didn’t look great, and some users thought their machines were compromised. Having looked in to it, it’s a problem with the headers in the .htaccess file. To resolve this error (I’ve seen a number of users with this issue), add this block to your .htaccess file.

<ifModule mod_headers.c> 
Header set Set-Cookie wordpress_test_cookie=WP+Cookie+check 
</ifModule>