I can't seem to play servers with custom maps. I know TF2 automatically download maps I don't have but for some reason when I try to join a server with a custom map, the map takes ages to download eventually ending in "Missing map maps/ctf_custom_example.bsp, disconnecting" message, on some servers sometimes asking if I should blacklist server before this message. It's frustrating and dunno what the cause of this problem and want to play custom maps.
Any help? Also I am set to "Allow all custom files from this server" and Steam is permitted on my firewall.