Xampp is not recognized VirtualHost after few attempts? - php

Question

I had installed xampp few years ago. But now I have a little problem with the configuration of the vhost.
I have 4 different pages in my server, the apache is running with the port 80. So my configuration to the vhost is as following:
NameVirtualHost *:80
<VirtualHost *:80>
DocumentRoot "C:/xampp/htdocs"
ServerName localhost
</VirtualHost>
<VirtualHost *:80>
DocumentRoot C:/xampp/htdocs/paginasweb/munkys
ServerName www.munkys.com.co
<Directory "C:/xampp/htdocs/paginasweb/munkys">
Options Indexes FollowSymLinks Includes ExecCGI
AllowOverride All
Require all granted
Allow from all
</Directory>
</VirtualHost>
<VirtualHost *:80>
DocumentRoot C:/xampp/htdocs/paginasweb/flinda
ServerName www.flinda.com.co
<Directory "C:/xampp/htdocs/paginasweb/flinda">
Options Indexes FollowSymLinks Includes ExecCGI
AllowOverride All
Require all granted
Allow from all
</Directory>
</VirtualHost>
<VirtualHost *:80>
DocumentRoot C:/xampp/htdocs/paginasweb/pluxpc
ServerName www.pluxpc.com.co
<Directory "C:/xampp/htdocs/paginasweb/pluxpc">
Options Indexes FollowSymLinks Includes ExecCGI
AllowOverride All
Require all granted
Allow from all
</Directory>
</VirtualHost>
<VirtualHost *:80>
DocumentRoot C:/xampp/htdocs/paginasweb/conradoarte
ServerName www.conrado-arte.com.co
<Directory "C:/xampp/htdocs/paginasweb/conradoarte">
Options Indexes FollowSymLinks Includes ExecCGI
AllowOverride All
Require all granted
Allow from all
</Directory>
</VirtualHost>
My problem is the following:
When I tried to join to my website, www.conradoarte.com.co, the page is loading outside the local network but after a few minutes or attempts the dns is lost, but if I join to the website inside my local network the page is up. After reload the page from my local network I can see again the page outside the local network.
I don't know what is the real problem.