LAUNCHXL2-570LC43: Issue using External Debugger (XDS110) on LAUNCHXL2-570LC43

Part Number: LAUNCHXL2-570LC43

Tool/software:

Hello,

Currently I am trying to debug my LAUNCHCXL2-570LC43 using XDS 110 External Debugger. It has J18 Header which is used for external debugging. I have connected JTAG TI14 Pins Header with J18 (which has 20 pins).
I have also linked Pin 8 and Pin 10 of J18 together and they are further connected to Pin 8 (GND) of JTAG Header. Similarly, I have linked VTref and nTRST pins as well. 

I have given 3V3 external power supply to J1 pin 1 (+3V3/6.6C). 

But when I debug my code using CCS then I get this type of error :
 

   "Error connecting to the target:
   (Error -2131 @ 0x0)
    Unable to access device register. Reset the device, and retry the operation. If error persists, confirm configuration, power-cycle the board, and/or try more reliable JTAG settings (e.g. lower TCLK)."
                    

When I checked VTRef using multimeter then I get 3V3 which verifies that Onboard debugger is successfully isolated. What I think is that I need to Isolate Voltage regulator as well. (I have also tried to provide +5V Dc voltage using +5V Dc Optional Jack on Launchpad but didn't work).

What could be the possible reason of it? Do I really need to isolate Voltage Regulator? 

Regards 
Radha Kishan Sharma