You'll get a black screen if any of these 3 steps haven't been done correctly.

Double check all your settings and in particular check that the External URL and PCoIP External URL are set correctly on your Security Server. These must contain names/addresses usable by the client to connect to the Security Server.

If it still doesn't work - go through the video for a complete worked example. You don't need to watch the whole thing, you can skip to about 18 mins in for the details of setting this up.

Use netasat -an to check that your Security Server is listening on UDP 4172 and TCP 4172.

Make sure PCoIP isn't being blocked anywhere. The logs and wireshark traces may help you.

If you still can't get it configured correctly, give us more details of your setup and someone will be able to help you further.

Mark.