From a community user report in https://www.mongodb.com/community/forums/t/a-small-mistake-in-upgrate-a-cluster-to-use-tls/166088

There is a small mistake in this documentation: https://www.mongodb.com/docs/manual/tutorial/upgrade-cluster-to-ssl/

When selecting “Configuration File Options” is shows net.tls.PEMKeyFile which is not a valid config option.

It should be net.tls.certificateKeyFile.