Adding the following text to a page in the Text editor and clicking Update results in “Error 404 – Page Not Found”:
2 = 2^1
Replacing this text with anything else makes the Update succeed.
Any ideas what might be causing the error?
Update:
After some experimentation I’ve discovered a more general form of input leading to errors:
<number> = <number> ^
with the same number on both sides of the equal sign.
For example, 100 = 100 ^ gives an error while 100 = 101 ^ doesn’t.
This is an issue when installing mod_security2.
The solution is as simple as disabling mod_security or allowing that page to POST that request.
The issue is that mod_security thinks someone is trying to hack into your site.