First of all power your board and probe off and on again before making any more attempts to debug. We've noticed that external probes work more reliably if you turn the board on before the probe is powered up.
Also before making another attempt to debug, make sure that all debug related tasks have closed down cleanly, using the "Clean up debug" button on the main tool bar.
Make sure that JP2 is fitted on your LPC-Link2 : we've noticed that these boards don't seem to provide the VTREF back to LPC-Link2 reliably (see Design Considerations for Debug ).
Also remove the jumpers J32 and J33 on your RT board and provide external power - with J1 jumpered appropriately.
Finally please note, that we have issued an updated version of our doc on using MCUXpresso IDE with the RT1050 board towards the end of last week. So even if you have looked at this previously, it might be worth having another look through:
Regards,
MCUXpresso IDE Support