
If you examine the Citrix Workspace App connection details in the Connection Center, you will see that DTLS over UDP is configured.

The ICA session seems to be established on the VDA server side but there is no activity on the client side. Users get either a black or a grey/white screen. You have eliminated all other potential issues and the root cause seems to be network related. You may review the separate article on troubleshooting black, white and grey screens of death in Citrix Virtual Apps and Desktops. In most cases the issues manifestate with black screen or grey/white screen for end users when they try to launch a hosted app or desktop. You are experiencing intermittent Citrix Virtual Apps and Desktops connection issues, which you suspect are network related.
