FormMail Error occurred

What does this mean and how to I fix it?

The following error occurred in FormMail :
Server attack "Many URLS in a field" detected. Your server is safe as FormMail is invulnerable to this attack. You can disable these messages by setting ALERT_ON_ATTACK_DETECTION to false in FormMail's configuration section.
More information:
Field "Comments" contained 3 URLs

email:
realname:


Referring page was KERRVILLEAREATOASTMASTERSCLUB.COM
SERVER_NAME was kerrvilleareatoastmastersclub.com
REQUEST_URI was /SureMail.php

User IP address was 66.146.237.253
User agent was Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.62 Safari/537.36

Alan D Ayers, DTM, Sgt@Arms

8544 Kerrville Area Toastmaster

It is exactly as it says someone tried to hack the contact mail form and our software stopped the hack.
FTH does not use PHP does not allow PHP anywhere on our servers.