We have an ERP system which is built on the Magic uniPaaS framework (not by us, it's a 3rd party solution, and we don't have the source code). We have recently moved the deployment of this application fully to Citrix Xenapp 7.5 (before we had some users working through Xenapp 5). We are using 2 application servers on which the application actually runs, a storefront server and a license server. Citrix is supposed to load balance the application across both application servers (we're using the software load balancer, we don't have Netscaler). All are virtual servers (HyperV) running Windows 2008 R2 as their OS.
This worked reasonably well for a few months, but it's always been a little fickle. Sometimes the application wouldn't start (it would show "connection established, negotiating capabilities" and then just close without launching the application). Sometimes we get a message that the server doesn't accept connections. Sometimes we get a message there's no citrix server configured on the specified address. While this used to be sporadic, since this week it's become virtually impossible to connect to the application. I'm not entirely sure what has changed, and the people who are supposed to manage Citrix internally do not have the necessary knowledge and skills to troubleshoot this issue (despite their claims to the contrary). My Citrix knowledge is limited, but I can't sit and wait for others to solve this any longer.
Any advise on where/how to begin to troubleshoot this issue would be greatly appreciated.