No, it's not happens on your demo website.
Yes I upload the htaccess after this change. My website is in subdomain, is it good?
Code:
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.smoother.biz$ [NC]
RewriteRule ^(.*)$ http://cart.smoother.biz/$1 [R=301,L]

## If you'd like your site to go to http://mysite.com instead of http://www.mysite.com, add these changes instead:

##RewriteEngine On
##RewriteCond %{HTTP_HOST} ^cart.smoother.biz$ [NC]
##RewriteRule ^(.*)$ http://cart.smoother.biz/$1 [R=301,L]

Thanks for your help