CPF is configured between multiple LPARs. While issuing change logonid command on one LPAR, get CAS5121E CCI CONV error - RC= 08 RS= B0 ERC= B0000000.
Release : 16.0
Component : ACF2 for z/OS
RS=B0 means CCILGR is not active and it's unable to open logger database.
Verify CCILGR is active on all LPARs by issuing /F CCILGR,DBSTATUS command. Start CCILGR on each LPAR (depending on your setup) if it's not active.