While managing a Bludit-based website, clicking "Save" in the backend settings page suddenly resulted in a "denied by modsecurity" error, preventing all modifications from being submitted. After investigation, the website root directory .htaccess configuration was confirmed correct, and server permissions were normal. The root cause pointed directly to the hosting provider's server ModSecurity security module.

Acting as a Web Application Firewall (WAF), ModSecurity often misinterprets legitimate operations as attacks due to overly strict rules. The particularity of this issue was: the interception was triggered only when the social media settings fields contained full URLs (such as GitHub, Twitter profile links). Clearing these fields allowed the save operation to proceed immediately.