Unable to launch published application - Specific client, in the Client / End User Issues forum on BrianMadden.com

n through WI. We have PS 4.5 Platinum, win2k3 servers.

Issue: Unable to open any published application through Web Interface, as user is getting an error.

Error:
Citrix HDX Engine has encountered a problem and needs to close. We are sorry for the inconvenience.
If you were in the middle of something, the information you were working on might be lost. For more information about this error click here

Error Details:
When user tried to click on published application, it brings this error and never launches the application.

If we choose Click here on the above error message it shows
Error Signature:
AppName: wfica32.exe
AppVer:13.0.0.6685
ModName: sslsdk_b.dll
ModVer:12.1.4.56357
Offset:0000bd0d

If I look into the client desktop's event viewer it shows Application Error, Event ID: 1000, Description: above Error signature.

Trouble happens on only a specific client.
Client had dual monitors and somewhere I heard dual monitor setting could cause issue, hence even disabled the dual monitor and still same.
Client has an option to connect to two differnt networks (external and internal), strangely the trouble only happens on the external network, through which they use VPN and connect. It is their business requirement to connect through the external network. The same works fine on internal network without trouble.

I have tried uninstalling and reinstalling the Citrix online plugin 12, also upgraded to Citrix Receiver and still having the same trouble. I know this is client specific but unable to determine what is causing this. Do anyone came across this issue and able to identify what is causing or how to resolve?