---- Begin output of java -jar "/tmp/kitchen/cache/jenkins-cli.jar" -s http://localhost:8080 -ssh -user "xxx" -i "/tmp/kitchen/cache/jenkins-key" install-plugin https://xxx:yyy@example.com/plugin.hpi  ----
           STDOUT: Installing a plugin from https://xxx:yyy@example.com/plugin.hpi
           STDERR: Feb 09, 2021 8:42:31 AM io.jenkins.cli.shaded.org.apache.sshd.common.util.security.AbstractSecurityProviderRegistrar getOrCreateProvider
           INFO: getOrCreateProvider(EdDSA) created instance of io.jenkins.cli.shaded.net.i2p.crypto.eddsa.EdDSASecurityProvider
           
           ERROR: Unexpected exception occurred while performing install-plugin command.
           java.io.IOException: Server returned HTTP response code: 401 for URL: https://xxx:yyy@example.com/plugin.hpi
                at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1900)
                at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1498)
                at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:268)
                at java.net.URL.openStream(URL.java:1068)
                at org.apache.commons.io.FileUtils.copyURLToFile(FileUtils.java:1111)
                at hudson.cli.InstallPluginCommand.run(InstallPluginCommand.java:110)
                at hudson.cli.CLICommand.main(CLICommand.java:249)
                at org.jenkinsci.main.modules.sshd.CLICommandAdapter$1.run(CLICommandAdapter.java:37)
                at org.jenkinsci.main.modules.sshd.AsynchronousCommand$1.run(AsynchronousCommand.java:112)
                at java.lang.Thread.run(Thread.java:748)