When trying to launch a Citrix application or desktop, you get this error:
The Citrix server has reached its concurrent application limit for this application. Please contact your Systen Administrator.
This is because there’s a setting that has been set in Citrix AppCenter to limit the number of concurrent connections to the application or desktop. The Citrix server will state that it has reached its concurrent application limit for the application erroneously (kind of), if users have not ended their sessions correctly.
To fix this, log off any disconnected sesssions to reduce the number of concurrent connections and teach users to log off, rather than disconnect. You may also wish to use a policy to log off disconnected Citrix sessions. If you still get the issue, restart the Citrix server (or just the Independant Management Architecture service). If you still get this issue, you can set the application to allow more than one instance of the application per user (right click the application in the AppCenter and go to the Application Properties. Under Advanced -> Limits, untick Allow only one instance of application for each user).
Alternatively, you could get the Citrix server has reached its concurrent application limit legitimately. Often such a limit if imposed for licensing or performance reasons. To increase the limit, right click the application in the AppCenter and go to the Application Properties. Under Advanced -> Limits, either untick the Limit instances allowed to run in server farm tickbox, or increase the maximum instances.