It looks like the endsbs *all *immed part of the command is not finishing. Is Qctl your controlling subsystem?
You can take a system request 3, then option 10 to view your joblog to see if there are any other more informational low level error messages.
Some system jobs can take a while to complete.
What you need to see in order for things to proceed is the message “system ended to restricted condition” in the qsysopr message queue before the savsys portion of option 21 can continue. System request 6 can show you qsysopr if you are running option 21. You will need to command 12 back for the option 21 to continue.