Issue is caused by the proxy defined on the client which blocking  access to the Netscaler PoPs used by Citrix DAAS .

See https://docs.citrix.com/en-us/citrix-gateway-service/pops-citrix-gateway-service.html

To verify if a proxy is in place on the client enter "netsh winhttp show proxy".

If the proxy is disabled then the issue no longer happens .

On the proxy configure an  exception to SSL-Decryption for global-all.g.nssvc.net

Previously an exception was configured for global.g.nssvc.net. However both  URLs are used by Citrix DAAS and must have an exception.

The recommendation is to use a wildcard and make  an exception for *.nssvc.net (including all sub-domains).

https://docs.citrix.com/en-us/citrix-gateway-service/pops-fqdns/commercial-pops

CWA Windows - get following error launching applications or desktops.

"Failed to connect to the server for your session. Try again or contact your Helpdesk with the following information: Error code: 2064.2708"

Issue is seen with CWA Windows and not with CWA for HTML5 Web Cient .