How to set off from from electronic liability register

sir I am a composite dealer and I submit all the cmp08 for 19-20 and submit annual return in gstr4 also for the year 19-20
now when I tried to submit cmp08 for 2 qtr 20-21 portal said clear previous tax liability the I saw a Rcm payment is due for the 19-20 now I tried to file drc03 to setoff previous year liability then portal said clear all liabilty of previous tax
so tell me how to clear previous year liabilty and set off all the payment so I submit cmp08 2qtr also for this year