ABEND = 84000FF7 and / or ABEND = 84DC2000

CFT LOG shows:
09.13.14 STC70816  CFTI21F ID= NETTCPIP Resource define failure CS=00000003 NET=
09.13.14 STC70816  CFTI15F Error code 00000003 _ Trying to define resource NETTCPIP

Since the latest SP/patches for V241, and with any of the V 2.6.X product makes used of the IARV64.
SYS1.PARMLIB (SMFPRMxx) must be updated accordingly.

Note:
DC2 ABEND can also occur when the product memory region is too low; it is mandatory to set the region parameter to 0M but you must also verify what amount is allow when 0M is set in a job.

A workaround to bypass the default value when 0M is set in the region parameter is to update the JCL with parameter MEMLIMIT in the CFTMAIN exec step:

I.E.:
CFTMAIN   EXEC PGM=CFTMAIN,REGION=0M,TIME=1439,MEMLIMIT=512M,        
        PARM='&ID'