WSFullResult does not give Results when we input failed WUiD

I am trying to read out the failed WU results, to tweak my code to restart the job from where it was left when the WU was failed, but when I use WSWorkunis\WUFullResult for reading the results from the failed Workunit, I get only info, warning and errors but no results.

The same gives results if the workunit is with completed  state, please help.