@pranavi 

If you are saying the same flow action is working fine in other instance then there is no issue in your JSON parser step etc

Seems you are not able to get the data and hence parser logic is failing

try to add logs and verify

Is input to JSON parser step an output from Powershell? If yes then that could be an issue with mid server and powershell didn't work and it broke the parser step

If my response helped please mark it correct and close the thread so that it benefits future readers.