I recent encounter this issue with one of my joomla site, i got a solution to it and i decide to share it. I visit my joomla site and all i see is 403 Forbidden access denied firstly i thought my site has been hacked so i log into my cpanel but no file or folder was missing or destroyed next i try to check my file or folder permission error so i review my folder permission but it was all at standard permission then i thought it from my .htaccess file it try to edit it i make some changes but it wont work then i try to check html codes but no error tags or codes, i even check my SQL database but they are all intact and no table or field was missing i try to upload an html file into my root folder and named it index.html but it wont show, i cant even access my administrator back-end i spent almost four hours trying to get what the problem was i even try to restore my back up file but still the same thing the back up wont even work, but i later make the smart move by contacting my hosting company they were able to disable and re-enable my account and that solver the problem none of us can explain what really happen but when my account was suspended and re enabled that solve the whole problem.