If you get blocked again and again by Mod_security so you have to follow these steps -
Reason – Modsecurity blocks it because it has the word “cookie” in it, but its security can’t be that clever because it doesn’t see it if its part of another word.
Solution -
By re-naming the file you can stop the ModSecurity from kicking off.
1. Rename jquery.cookie.js to jquerycookie.js from your hosting control panel. (take out the middle dot)
2. Edit the header template that loads it:
catalog/view/theme/default/template/common/header.tpl to take out the dot aswell.
http://blog.zolute.com/opencart-gets-blocked-on-mod_securityresolved/