Error message #
"The published resource is not available currently. Contact your system administrator for further assistance."
Symptoms #
Running into this issue intermittently with Citrix Virtual Apps and Desktops LTSR 1912. It doesn't seem to be affecting all users. Sometimes it works immediately and sometimes the affected users usually have to try 2-3 times before the published application finally opens. Once connected there are no issues.
Root cause(s) #
As per one potential root cause is the following.
This can becaused by MTU settings. In case an environment has GRE tunnels inside site-to-site VPN tunnels then the problem can affect all users utilizing the VPN connection via GRE. Also the issue can occur in cases with a third party VPN solution like Cisco AnyConnect, when using Citrix Gateway hosted on Azure, when connected to certain Wi-Fi networks or mobile networks (3G, 4G, etc).
Different types of networks may have different MTU/MSS requirements, which may result on packets being fragmented when transmitted on those networks. This can cause issues with applications that use UDP as transport protocol due to improper handling of UDP packet fragmentation. In the case of Citrix XenApp and XenDesktop / Virtual Apps and Desktops, this affects EDT since it is a UDP-based protocol. These issues can result on performance issues in ICA sessions, on EDT connections failing and falling back to TCP, or even not being able to establish a session altogether.
The error presented in this article can also be due to missing RDS CAL licenses. It is imperative to always check server logs and Citrix application error codes before deciding upon an action plan to mitigate the Citrix error.
There are however multiple other possible root causes for this issue and therefore any troubleshooting efforts should always commence with sufficient level of root cause isolation.
Resolution #
If the error is network/MTU related, follow step-by-step instructions available at https://support.citrix.com/article/CTX231821.
Given this is a very generic error message with many possible root causes, always apply the method of isolation to determine the root cause of the error in your unique environment.
First try client-side investigation as per the following Citrix article pointing to DTLS configuration: https://support.citrix.com/article/CTX235241
Also check potential Citrix Gateway related root causes, one example is provided in the following article: https://support.citrix.com/article/CTX233005.
The issue is further discussed in the following Citrix article: https://discussions.citrix.com/topic/392471-citrix-receiver-the-published-resource-is-not-available-currently-contact-your-system-administrator-for-further-assistance/.
You can find more detailed guidance and step-by-step procedures for analyzing and troubleshooting Citrix Virtual Apps and Desktops organized by category in my Citrix Virtual Apps and Desktops Troubleshooting e-book.
