When i Favorite a killing floor server it wont work

When i favaorite when of the 5 killing floor steam gamer servers it wont show up when i search on my favorites even after i refresh it.

Try copying the IP address and click on the favorits tab. Then just click Add a Server, paste it, find it, then add it. It should appear

You are going to have to manually search for that server on the server list, right click it, and click on "Add to Favourites". Doing it while playing in the server won't work.