DNS error with dynamic subdomains with htaccess

Question

I am trying to implement dinamics subdomains for cities, but this does not work when the subdomain is used. My htaccess:

Options +FollowSymlinks <IfModule mod_rewrite.c> RewriteCond %{HTTP_HOST} ^www.bisnet.com.co [NC] RewriteRule ^(.*)$ http://bisnet.com.co/$1 [R=301,L] </IfModule> <IfModule mod_rewrite.c> RewriteCond %{HTTP_HOST} ^www.bisnetcolombia.com [NC] RewriteRule ^(.*)$ http://bisnet.com.co/$1 [R=301,L] </IfModule> <IfModule mod_rewrite.c> RewriteCond %{HTTP_HOST} ^www.bisnet.co [NC] RewriteRule ^(.*)$ http://bisnet.com.co/$1 [R=301,L] </IfModule> <IfModule mod_rewrite.c> # Activar RewriteEngine RewriteEngine on RewriteBase / #RewriteCond %{SCRIPT_FILENAME} !-d #RewriteCond %{SCRIPT_FILENAME} !-f RewriteCond %{HTTP_HOST} !^www\.bisnet\.com\.co RewriteCond %{HTTP_HOST} ([^.]+)\.bisnet\.com\.co Rewriterule ^([0-9]+)\-([a-zA-Z0-9_]*)/([0-9]+)\-([a-zA-Z0-9_]*) http://bisnet.com.co/index.php?categoria=$1&empresa=$3&ciudad=%1 RewriteCond %{HTTP_HOST} !^www\.bisnet\.com\.co RewriteCond %{HTTP_HOST} ([^.]+)\.bisnet\.com\.co Rewriterule ^([0-9]+)\-([a-zA-Z0-9-]*) http://bisnet.com.co/index.php?categoria=$1&ciudad=%1 RewriteCond %{HTTP_HOST} !^www\.bisnet\.com\.co RewriteCond %{HTTP_HOST} ([^.]+)\.bisnet\.com\.co Rewriterule ^letra/([^/.]+) http://bisnet.com.co/index.php?categorias=$1&ciudad=%1 RewriteCond %{HTTP_HOST} !^www\.bisnet\.com\.co RewriteCond %{HTTP_HOST} ([^.]+)\.bisnet\.com\.co Rewriterule ^buscar/(.+) http://bisnet.com.co/index.php?q=$1&ciudad=%1 Rewriterule ^nosotros/(.+) http://bisnet.com.co/index.php?interna=$1 RewriteCond %{HTTP_HOST} !^www\.bisnet\.com\.co RewriteCond %{HTTP_HOST} ([^.]+)\.bisnet\.com\.co RewriteRule ^ http://bisnet.com.co/index.php?ciudad=%1 </IfModule> 

In http://htaccess.madewithlove.be/ the test looks fine, but I get an error on my server: ERR_NAME_NOT_RESOLVED

Test URL:

 http://bucaramanga.bisnet.com.co/ http://bucaramanga.bisnet.com.co/letra/a http://bucaramanga.bisnet.com.co/166-restaurantes http://bucaramanga.bisnet.com.co/166-restaurantes/355-la_casona_del_chingo 

Thanks for the help.