Some time the root domain .htaccess file rule affect to addon domains. So you can not access your addon domain properly. If you want to disable this rule for the addon domain then you need to add the following rule in the root domain .htaccess file.
RewriteCond %{HTTP_HOST} ^(www\.)?addon_domain\.com
Rewriterule .* - [L]
for example addon domain is indianwebportal.com then rule is
RewriteCond %{HTTP_HOST} ^(www\.)?indianwebportal\.com
Rewriterule .* - [L]
Note : Where addon_domain should be replaced by the actual domain name, and I’m assuming that both addon_domain.com and www.addon_domain.com exist and resolve to your server.
