Registered site redirects to Pro Site page

I'm seting up a test site and I've created a user with pro site membership with a subdomain.
This subdomain is always redirected to pro site page.
user subdomain is supermorph.predprod.architech.hr - this is redirected to http://predprod.architech.hr/pro-site/?action=new_blog as if the user has to create/register new site.

Can someone explain this ?