When bringing up RESTAPI you receive the following error
BPXP005I A FORK OR SPAWN ERROR WAS ENCOUNTERED. RETURN CODE 00000070 REASON CODE 0B17001F
Release : 12.0
Component : CA ESP WORKLOAD AUTOMATION
Did not have a definition for OMVS in SMFPRM member. When there is no OMVS definition it defaulted to the system definition, which includes IEFUSI. IEFUSI restricts the available region for a Started Task.
Added the following in SMFPRMxx member in sys1.parmlib.