Horizon Client — Black/Blank Monitor Display
Introduction
TranslationIf pending..a user sees a blank or black screen when launching the Horizon Client, several factors may contribute to the display. This article explains some of the most common causes of the Horizon black screen and provides corresponding solutions.
This troubleshooting guide applies to Horizon 8.
Causes of a blank/black screen
Various factors can cause a blank or black screen when connecting to Horizon View and establishing a VDI session.
Required Network Ports
For the Horizon Client to function properly, ensure the required ports are accessible.
The following ports are required when the Horizon Client connects directly to a Connection Server:
443
Login, authentication, and connection to the connection server
Horizon Agent
TCP
22443
Blast Extreme
UDP
22443
Blast Extreme
TCP
4172
PCoIP
UDP
4172
PCoIP
TCP
9427
Drive Redirection (CDR) and Multimedia Redirection (MMR)
TCP
32111
USB redirection (optional, can be integrated into Blast Extreme)
The following ports are required when the Horizon Client connects via a Unified Access Gateway (UAG):
443
Login, authentication, and connection to the UAG. It may also carry tunneled RDP, CDR, and USB traffic.
TCP
4172
PCoIP via PCoIP Secure Gateway
UDP
4172
PCoIP via PCoIP Secure Gateway
UDP
443
Use it optionally for login traffic. If TCP conditions are suboptimal, Blast Extreme attempts a UDP connection.
TCP
8443
Blast Extreme via Blast Secure Gateway (High-performance connection)
UDP
8443
Blast Extreme via Blast Secure Gateway (Customized Performance Option)
TCP
443
Blast Extreme via UAG Port Sharing
DNS Considerations
While Horizon View typically uses IP addresses for communication between the Connection Server, DNS issues can affect component performance.
Therefore, always ensure DNS functions correctly both internally and externally.
Correctly configure Unified Access Gateway (UAG).
A common cause of a black screen is an incorrectly configured Unified Access Gateway (UAG) for Horizon.
Configuration errors between the Connection Server and the UAG often occur during initial setup.
When configuring a UAG, disable both Blast Secure Gateway and PCoIP Secure Gateway on the Connection Server, as the UAG handles these functions.
Secure Gateway Settings When Using UAG
Another common issue occurs when the Unified Access Gateway (UAG) is misconfigured. Several important parameters must be set correctly. Enter the following values under Horizon Settings on the UAG:
https://ConnectionServerIP:443
Connection Server URL Thumbprint
sha1=SSLTHUMPRINT (Thumbprint of the View Connection Server’s SSL certificate)
PCOIP External URL
UAG-EXTERNALIP:4172
Blast External URL
UAG-InternetFQDN:443
Tunnel External URL
UAG-InternetFQDN:443
Additionally, install a valid SSL certificate under TLS Server Certificate Settings. Apply this certificate to both the admin and internal interfaces. Ensure the certificate matches the FQDN (internal and external) of the UAG appliance.