EclipseLink Jenkins server (https://ci.eclipse.org/eclipselink/) can't execute/proceed any job
Summary
Our EclipseLink Jenkins server (https://ci.eclipse.org/eclipselink/) can't execute/proceed any job. Console prints Waiting for next available executor
see e.g. https://ci.eclipse.org/eclipselink/job/eclipselink-cb-master/522/console
or https://ci.eclipse.org/eclipselink/ "Build Queue".
Thank You