Resolve WordPress Loading Error

My WordPress site has suddenly gone offline. Instead of my homepage, the browser returns an error screen that simply shows different folders in the directory No content loads at all. I need the site to display normally again and to understand what triggered the outage.

You’ll have full WordPress admin and cPanel/FTP access the moment we start. I’m looking for someone who can:

• Identify the root cause of the “site not loading” problem (server, .htaccess, plugin, theme, database, or PHP configuration).
• Remove or repair the fault so the site loads completely without the error message.
• Provide a short summary of the steps you took so I can avoid the issue in future.

Please let me know how quickly you can begin and roughly how long the fix is likely to take once you have access.