The ‘412 Precondition Failed’ error message may be displayed on any of the web pages of your website when you are trying to access it. It is shown because the respective web page is incompatible with certain security principles that the server has. These principles are generally utilized in order to protect the websites hosted over the server from any of the malicious activities. It is a part of the server management process.
The most common cause of this error is the mod_security setting. This response will be sent by the mod_security module when any portion of the data requested over the web has the possibilities to be malicious.