How to use lsnrctl with TCPS

Oracle 11.2.0.4

Linux:

(from uname -a) Linux <servername> 3.10.0-1062.1.2el7.x86-64

I've been away from Oracle for far too long, a 5 year sojourn in SQLServerLand. Now, I've suddenly inherited an orphan single instance oracle database and the customer wants me to apply Oct 2020 Critical Patch Update.

My stumbling block, as the title implies, is the TNS-01194 error, The listener command did not arrive in a secure transport. I found the document, How to Restrict the Lsnrctl Utility to Communicate with the Listener Using ONLY the TCPS Protocol (Doc ID 2280787.1). Its solution is to create a self signed certificate.

The directions do not appear to ambiguous, but even with all the care I can muster, I still do not have access to the listener and continue to receive the TNS-01194.