we had same issue where in we have restarted only sap and sapccm4x agent was not started since after sap restart.
we have followed below proceedure to start the sapccm4x agent.
sapccm4x pf=/sapmnt/<SID>/profile/<instance_profile> -initshm - to clear the shared memory
sapccm4x -DCCMS pf=/sapmnt/<SID>/profile/<instance_profile> - to start the agent
Regards,
PB