When opening Studio , it keeps on Expanding .Unable to run any Broker commands .
Session Launch is fine but cannot open Studio .

If you run commands like Get-brokersite or Get-brokercontroller , the command fails 
If you restart the Broker service on all the controllers in the SIte , the studio and the above command works for few Minutes but same issue after sometime .

Add this code to the broker service config File of the Controller and restart the service , it will generate the WCF logs . Before making the change please take a backup of the Config File .

Location C:\Program Files\Citrix\Broker\Service  File name : BrokerService.exe.config
 
<system.diagnostics> 
      <sources> 
            <source name="System.ServiceModel"  
                    switchValue="Information, ActivityTracing" 
                    propagateActivity="true"> 
            <listeners> 
               <add name="traceListener"  
                   type="System.Diagnostics.XmlWriterTraceListener"  
                   initializeData= "c:\log\Traces.svclog" /> 
            </listeners> 
         </source> 
      </sources> 
   </system.diagnostics> 
 
 
Snapshot in my Lab :
 


Now download the utility to check the WCF traces collected in above step:
SVCtraceVIewer.exe 
https://docs.microsoft.com/en-us/dotnet/framework/wcf/service-trace-viewer-tool-svctraceviewer-exe 

Check in the Trace file for Error or Exception , you may find the below error :

Warning:
Description    The system hit the limit set for throttle 'MaxConcurrentSessions'. Limit for this throttle was set to 200. Throttle value can be changed by modifying attribute 'maxConcurrentSessions' in serviceThrottle element or by modifying 'MaxConcurrentSessions' property on behavior ServiceThrottlingBehavior.

Error :Exception
Description 
The communication object, System.ServiceModel.Channels.ReplyChannel, cannot be used for communication because it has been Aborted.

If you see the above message in the trace do the following change in the file BrokerService.exe.config on all the controllers.

MaxConcurrentSessions: Your default is 200 * ProcessorCount increase the value 400 ·
MaxConcurrentCalls: Your default is 32 * ProcessorCount increase the value to 64

After making the above change restart the Broker service on all the controllers and Open the Studio .
 

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Problem Cause

Max throttling for Broker service has been reached .