The IBM CICS Connection could be seen to be in KO state when viewed via CEMT I CONN(MYCN) command on the Z/OS CICS region. If connect was release and acquired it would go into an OK state but after a period of time would revert to a KO state.  The OK status on the CEMT commands shows that the link is SYNCLEVEL 2 capable but if in KO status then any requests that required SYNCLEVEL 2 would fail.

Full article: https://portal.microfocus.com/s/article/KM000010721