ENF failed and restart successfully. Here are the error messages:

23.32.33 S0009446  CCSR021I OWNER = CA CCI R15.0                               
23.32.33 S0009446  CCSR022I MODULE = CAS9VTAM FMID = CAW1F00 RMID = SO08372    
23.32.33 S0009446  CCSR061I PSW: 00000000 00000000 070C1000 A5F7752E           
23.32.33 S0009446  CCSR062I ILC: 02 INTERRUPT CODE: 0D                         
23.32.33 S0009446  CCSR067I COMPLETION CODE U0600 REASON CODE 00000000         

Common Services 14.1 & 15.0 - z/OS supported releases -  

A U600 abend in CCI means an internal CCI Resource pool has been exhausted, this is a GLOBAL pool.

Any task looking for a resource when it has been exhausted would encounter this abend.  

The WLM service class for the address space should be increased to prevent this from occuring.