QUESTION:

Why do I get a “412 Precondition Failed” error when submitting a form?
“mod_security: Access denied with code …”
I get a mysterious server error when trying to save a page template or form.



ANSWER:

These and similar errors are usually caused by mod_security filtering. Some hosting companies use mod_security or other similar filters to block web form submissions containing certain key words or suspicious symbols, in order to prevent comment spam or hack attempts. Occasionally these security rules can block legitimate requests.

Textpattern never sends a 412 response.

You should raise a technical support ticket with your hosting company. There is nothing Textpattern can do to fix the problem.