Cannot find servers in community server

Hi, Why I cannot find servers in community server? My friends have many of them (10/20 servers) and I can find only 2 or 3 of them, this is forcing the group to play only the few I can find. The filters and the region (Eu, RU) are the same and we are playing from litterally the same town.
Thanks

Forward port range 27000-28000 onto your NAT IP in your router. Also modify Pings Per Minute settings in Steam client and see if it gets any better as you adjust this.