Page Hangs at agesso.jsp after Logging in Through Access Gateway on Netscaler 9.3

-update-
Please see the update version of this article here.

I recently ran into an issue where after logging in through Access Gateway on a NetScaler 9.3 VPX appliance, the page would seem to randomly hang on /Citrix/XenApp/agesso.jsp.  After looking at various logs and the configuration settings, I started looking at the authentication pieces.  Also, since it seemed to happen every other time someone logged in, I started looking at the STA and XML servers.

I ended up finding an issue with one of the XenApp servers.  And I was able to verify that was the culprit by setting the XML and STA services to one server and it started working consistently.  It looks like this has been happening for quite some time and probably when the servers were built, because I was having a computer SID issues on the culprit server.  I ended up doing a sysprep to randomize the SID and re-added that server back to the domain.  After the server was back online, I set NetScaler to use that server only for STA and XML and it worked consistently.  After I verified that it worked consistently, I set NetScaler back to using both servers for XML and STA and of course tested with success.

So, if you are running into this issue there are some other articles out there to check your DNS, routing, and certificates on the NetScaler.  But, you should also check your backend servers where the XML and STA services reside.