403 error on homepage after install in subdirectory

I’ve installed the latest Ghost on an new Ubuntu 18.04 server, following the command line install instructions.

Ghost is working perfectly at mysite.com/blog/

However, the index.html page previously showing at mysite.com is now showing a 403 error.

I believe this might be connected to the new SSL? I’m not sure which config files are now in use. I had written a simple conf at /etc/apache2/sites-available/mysite.com which was working to direct traffic to /var/www/html. Ghost is installed at /var/www/ghost. Do I need to change the config, or move non-Ghost site files somewhere else?

All help gratefully received.