Setup on GoDaddy / Addon Domain "403 Forbidden Access Error"
Solved## Successful installation completed :)
When setting the Directory Root for the &quot;multisite&quot; SiteY.com addon domain, I got it wrong.
Incorrect: home/.../public_html/xxxxx.com/sites/siteY.com

Correct: home/.../public_html/xxxxx.com/

With the correct option, you point to the site that contains the code based you want to pull from, as well as the index.php file.
I don't fully get the mechanics at play here, but am thankful to be on the other side.