For anyone who faced this problem:
after days of working to solve this I found files in: /usr/local/apache/conf.d/vhosts/
the domain who shows the default page has files in this directory named: exampledomain.com.conf.disabled & exampledomain.com.ssl.conf.disabled
JUST find these files and remove the last extension (.disabled) and Restart Web Servers (the easiest way to restart web servers from side menu WebServer Settings -> SSL Certificates page and then Restart Web Servers button on the top of SSL cetificates table).
I wish my comment will help somebody.