ModSecurity is an Application Firewall that filters, monitors, and blocks HTTP traffic to and from a web application. By inspecting HTTP traffic, it can prevent attacks stemming from web application security flaws, such as SQL injection, cross-site scripting (XSS), file inclusion, and security misconfigurations.
Items that are likely to be blocked or cause an error/conflict include the following.
📌Note: This is not an exhaustive list.
SRC
Style
()
!,=, <>
/bold
Using url's with ?ref=Link
images/logos
If you are getting a 403 error and are using any of these items in text or comment fields, you should remove them and save your input again.