It seems every 1 out of 3,000 users has a server with broken PHP
sessions that would require a trouble ticket with their web host to
fix. So I released a new version of Fast Secure Contact Form 3.1.8 that does not use PHP sessions anymore. I found and included a PHP session replacement called WP Session Manager that uses the WP database to keep the session token. The author gave me permission and including the library only took a few minutes to do. It is working better.