XenApp 6.5 Session launch is stuck at "Connection established. Negotiating capabilities"

XenApp 6.5 Session launch is stuck at "Connection established. Negotiating capabilities":

Error Message:

ICA connections become unresponsive generating the error "Connection established. Negotiating capabilities” specific to client workstation or domain user.
In addition, connecting to a specific server always stops displaying “Connection Established, Negotiating Capabilities”.

To resolve this issue we have two ways. Let us see them in the following.

Form1:

Step1:

On client workstations with this issue, change the permissions on the registry key HKLM\SOFTWARE\Microsoft\MSLicensing. Grant the Users group Full Control or specific domain user account.

If you delete the key, Terminal Services recreates it when it acquires a license. However, the permissions on this key are set to read-only by default. Only administrators have full control rights and can request a Terminal Services license for this server. After it is acquired, every user can use it.

Step2:

Delete the following keys:

HKLM\Software\Microsoft\MSLicensing\HardwareID
HKLM\Software\Microsoft\MSLicensing\Store keys

ClientLicense, CompanyName, LicenseScope, ProductID

Note: Ensure to back up the registry keys before deleting.

Form2:

Step1:

On each XenApp servers, open the registry editor and navigate to 

HKEY Local Machine/System/Current ControlSet/Services/TermService/Parameters.

Step2:

Delete the following keys (after saving a backup):

·         Certificate

·         X509 Certificate

·         X509 Certificate ID

Step3:

Restart the server and verify that the issue is resolved.

This issue can be caused by an inaccessible license server. Server results in not getting a correct license. If servers are cloned, license server detects that several servers are using the same license and blocks it