Problem:
Google has indexed the HTTPS version of my addon domain.
Solution:
Occasionally Google will index the HTTPS version of the addon domain, When the account has a SSL/TLS certificate. This causes the URL to change to https://www.maindomain.com/folder/ this causes incorrect cataloging of page information.
To ensure this does not occur please add the following to the .htaccess file.
RewriteEngine On
RewriteCond %{HTTP_HOST} ^domain.com$ [OR]
RewriteCond %{HTTP_HOST} ^www.domain.com$
RewriteCond %{SERVER_PORT} ^443$
RewriteRule ^(.*)$ http://www.domain.com [R=301,L]
Note: Substitute domain.com with your website name.