Using jenkins-cli with public key authentication.

jenkins-cli -s http://localhost:8080 help

works.

Using jenkins-cli with public key authentication.

jenkins-cli -s https://jenkins.example.com help

fails with a 403.

Exception in thread "main" java.io.IOException: Server returned HTTP response code: 403 for URL: https://jenkins.example.com/cli
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1403)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
at hudson.cli.FullDuplexHttpStream.<init>(FullDuplexHttpStream.java:61)
at hudson.cli.CLI.<init>(CLI.java:110)
at hudson.cli.CLI.<init>(CLI.java:82)
at hudson.cli.CLI._main(CLI.java:250)
at hudson.cli.CLI.main(CLI.java:199)

Apache configuration is a simple vhost with ProxyPass/ProxyPassReverse at the root.