When configuring system in Jenkins (Jenkins --> Manage Jenkins --> Configure System) I locate the 'Publish over SSH' section and click 'Add'. I enter a 'Name', 'Hostname', 'Username', and 'Remote Directory'. I then click on the 'Use password authentication, or use a different key' checkbox. I enter the appropriate 'Path to key' to a known good ppk for an ssh key for connecting to a Linux server. When I click on Test Configuration I get the following error:
Failed to connect or change directory
jenkins.plugins.publish_over.BapPublisherException: Failed to add SSH key. Message [invalid privatekey: TheKey]