all subdomains are redirected to filerun

Hello,

I've setup Filerun so it would be under files.mydomain.pl but for some reason if I type whatever.mydomain.pl it still redirects to filerun, which is not a behaviour I'd like. It's meant to work only under a single subdomains, but it keeps redirecting to Filerun regardless of what subdomain I use.

I'm using apache2 and here's my filerun.conf

https://pastebin.com/uvCYVAJU

Can anybody point out what's wrong here or how it should be done correctly?