A number of job submissions through Control-M (MFBSIJCL) causing some jobs to fail with RC=209
Diagnostics, MFBSI logs and JES output show :

MFCC error in MccMfbinpCall:mf/log/mfbsi/<REGION_NAME>/jcltemp/test.jcl.003208578@srv01.mf.local"
MFCC request timed out

JCLSI0001I JCLSI0034E Unable to submit the JOB to the Server  (cassub api RC=015).
JCLSI0001I JCLSI0034E Unable to submit the JOB to the Server  (cassub api RC=015).
JCLSI0001I JCLSI0035E => CASSUB Parms error/Server not found/Server shutted-down/Communication error?
JCLSI0077I JOB Ended with OS RC=0209.

Full article: https://portal.microfocus.com/s/article/KM000016075