many times for some reason when u press save in opencart admin panel u get this
You don’t have permission to access /admin/index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
and start digging around and most of the times it is the same solution which i keep forgetting it is server issue and the answer is :
Mod_security is blocking this operation
so u need to talk to the hosting support to fix this and all will be alright