This error is reached after clicking an app in Storefront.
The STA(s) on the NetScaler Gateway vServer do not match what is configured on Storefront. These need to be the same. Check both, and update accordingly.
You do not have a certificate bound to the NetScaler and/or the XenDesktop/XenApp servers. Add a certificate to the NetScaler and XenDesktop/XenApp servers.
OR…. Change your STAs to http. Make sure you do this on both NetScaler Gateway vServer and Storefront.
You may not have the correct ports open for HTTP/SSL traffic on your firewall. Add a rule to your firewall allowing port 80 and/or 443.
All of your TS/RDS licenses are currently checked out. Add more licenses or log out of a session. See this article if you are experiencing this for VM-hosted apps
CTX132334 – Secure Ticket Authority (STA) Status is Marked as DOWN for the Access Gateway Virtual Server