TNS-12679: Native services disabled by other process but required

Interesting error today on a Oracle 19c database server, which had been running just fine for month.

After a listener restart last night and some config file confusion for said listener, I got alerted this morning that the listener was spawning TNS-12679: Native services disabled by other process but required errors.

As usual, the Oracle help center was useful:  https://docs.oracle.com/en/error-help/db/tns-12679/?r=19c :

Action

Enable native services on the remote process or disable them locally.

What "native services"?

As I wrote before, there was some config file confusion. This is mainly because we inherited these Oracle DB servers and are in the process of moving files and folders into our standard layout. This means that in the interim some files are double and then it depends on the environment you use which is config files are actually used.

In this specific case, the one used is the new one we want to introduce which has strict encryption settings:

Not all clients seem to connect encrypted, hence the error that a native service was missing. So to get things working, I changed the setting to:

Agreed, not the best solution, but now the systems work and I need to talk with some system owners about how they connect to the database (Oracle Client? ODP? dotNET?) and see if we can get them to en encrypted state.