Not sure whether you are facing the issue or providing the steps for the resolution :-)
However if you are facing the issue, then ensure that you have provided the correct password(-p) value in the pmcmd command.
pmcmd startworkflow -sv IS_TEST_DIT -domain DOM_TEST_DIT -u tbasil -p <password> -paramfile /var/prod/l2c/source/work/test.prm -f L_TEST -wait wf_TEST
If the issue still persists, try once using the default Administrator user and see if command executes successfully.
We are too facing the same issue with same error code with version 9.5.1 HF4.
Note : we gave the correct password at the pmcmd level and also tried with native user still getting the same Error.
Any help on this will be appreciated