Due to recent security updates, ownership of addon domain and subdomain folders were changed from user:nobody, to more the more secure set user:user.
For some accounts or portions of an account, this resulted in a 403 Forbidden error seen on certain subdomains or addon domains. This can be easily fixed by setting 755 permissions for the addon or subdomain's folder in cPanel File Manager.
If you are new to changing permissions, the video tutorial below should be in good use for you:
Web Hosting Video Tutorials
If you would prefer we change permissions for you, please open a ticket.