This issue can arise if port 3389 is not listening on the VDI Computer.
The remote display protocol port refers to TCP Port 3389 (Remote Desktop Protocol) which is not enabled on the Virtual Desktop machine.
If deploying VDI machines via the vWorkspace management console through VMware,SCVMM or Virtual Iron, you need to edit the Template to enable Remote Desktop Services on the machine.
1. Login to the machine having the issue
2. Right click My Computer |select Properties
3. Select the Remote tab
4. Check the box Allow users to connect remotely to this computer
5. Click OK
6. Reinitialize through the vWorkspace Management Console