Few clients gets Black Screen and then gets Disconnected

[Techstarts]

Hallo All,

We have recently upgrade horizon environment to 7.11

All of us are able to connect to the platform. From inside and outside.

But only one of our partner (Out of our organization) are not able to connect to Windows 10. But other partners are able to connect. 

One of the issue they are facing is Black screen. 

This means they are authenticated and proceed with remote session. But after that they see black screen.

Initially I observed they were using 4.x client. I asked them to upgrade to 5.x But it apparently same problem.

Any Idea what else should I troubleshoot? Only specific Partner is facing this issue.

Appreciate your help.

[Techstarts]

Hope it helps someone.

99 out of 100 times, when you see blackscreen issue. it is Firewall issue. Keep this in mind.

Only thing you need to further investigate where the firewalls are involved.

In this case, there was firewall enable only for PCoIP and hence it worked. But the moment the user selected Blast, it failed.

Another important thing to remember, you must enable UDP in both the direction.

My respect to the team who saw this portal as necessity --- https://ports.vmware.com/