WordPress multisite permalinks problem

I have a subdomain wordpress network. I have around 50 sites in my network My host is a virtual host. So permalinks not working. I added the following code

<VirtualHost *:80>
  DocumentRoot /var/www/vhosts/wordpress
  <Directory /var/www/vhosts/wordpress>
    AllowOverride Fileinfo Options
  </Directory>

and its partially working. I mean new site permalinks in my wordpress network working properly. But old site permalinks not working.

Let say i have a old site called old.mysite.com

I couldn’t access that site. Chrome says

Oops! Google Chrome could not find old.mysite.com
I can access my main site mysite.com But the post permalinks not working. Its redirecting me to mysite.com/wp-admin/

Everything work properly in my new site new.mysite.com

Can anyone tell me how to fix my old site permalinks?. Thanks