The only case when that error mentioned above comes up is:
When you haven't connected the J-Link Debugger to the PC when starting the debug configuration as it is not able to reach the debugger in the first place.
So, please connect the debugger to the PC and then start the debug config. It should work as expected.
I have re-produced this on my end.
The J-link Debugger is correctly connected via USB and its green LED is powered on, and I still have the same error message.
The JTAG debugger is also correctly connected to the RDK board.
Can you just clarify if you have done any changes to the power domains of CX3 RDK?
If yes, can you elaborate what all you did?
The error that you see above also comes when the JTAG block of CX3 doesn't get powered up properly and has some issues regarding the power domain.
Also, can you confirm that it is a CX3 RDk board from e-con systems and not a custom board?
Please follow section 3.1 of EzUsbSuiteUserGuide.pdf found in the path: C:\Program Files (x86)\Cypress\EZ-USB FX3 SDK\1.3\doc\firmware\EzUsbSuite_UG.pdf
The document mentions the correct debug configuration that needs to be followed.
Also, the initial speed in the Debugger tab is to be Fixed at 1000KHz.