If you have a problem with newsletter signup forms imported from our demo content, then you need to make a little fix in custom form. Navigate to Newsletter > List Building (top navigation) > Custom Forms and change used URL to meet you requirements.
For instance, Liberty theme export file will have this line:
<form method="post" action="http://localhost/liberty/?na=s" onsubmit="return newsletter_check(this)">
so all you have to do is to change it to read
<form method="post" action="http://%YOUR_URL%/?na=s" onsubmit="return newsletter_check(this)">
Please check following image:
