ERROR: invalid PSK settings

I am compiling the “examples/simplest_web_server_ssl” on a OpenBSD 6.8 (amd64) with latest patches and updates (LibreSSL 3.2.2). However, after compilation succeeds, and try to run the program, I get the following message:
“Starting SSL server on port 8443, cert from server.pem, key from server.key
Failed to create listener: Invalid PSK settings”

Which of course does not happen under Linux running OpenSSL 1.1.1g

Does this problem is related to the flavor of the SSL library?

LibreSSL does not support PSK.

The error message comes from here.