java.exe -Xrs -jar "%BASE%\swarm-client-3.17.jar" -mode exclusive -name *** -labels *** -executors 1 -master [http://***] -username *** -password *** -fsroot "%BASE%" -deleteExistingClients -labelsFile "%BASE%\labels"

Feb 10, 2020 10:25:50 AM hudson.plugins.swarm.SwarmClient discoverFromMasterUrl
SEVERE: Failed to fetch slave info from Jenkins, HTTP response code: 500
Feb 10, 2020 10:25:50 AM hudson.plugins.swarm.Client run
SEVERE: RetryException occurred
hudson.plugins.swarm.RetryException: Failed to fetch slave info from Jenkins, HTTP response code: 500
	at hudson.plugins.swarm.SwarmClient.discoverFromMasterUrl(SwarmClient.java:248)
	at hudson.plugins.swarm.Client.run(Client.java:130)
	at hudson.plugins.swarm.Client.main(Client.java:104)Feb 10, 2020 10:25:50 AM hudson.plugins.swarm.Client run
INFO: Retrying in 10 seconds 

2020-02-10 09:50:32.698+0000 [id=276]   WARNING o.e.j.s.h.ContextHandler$Context#log: Error while serving http://***/plugin/swarm/slaveInfo
java.lang.NoClassDefFoundError: hudson/UDPBroadcastFragment
        at hudson.plugins.swarm.PluginImpl.getSwarmSecret(PluginImpl.java:262)
        at hudson.plugins.swarm.PluginImpl.doSlaveInfo(PluginImpl.java:272)
        at java.base/java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:710)
        at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:396)
Caused: java.lang.reflect.InvocationTargetException
        at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:400)
        at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:408)
        at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:212)
        at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:145)
        at org.kohsuke.stapler.MetaClass$11.doDispatch(MetaClass.java:535)
        at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
        at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:747)
        at org.kohsuke.stapler.Stapler.invoke(Stapler.java:878)
        at org.kohsuke.stapler.MetaClass$4.doDispatch(MetaClass.java:280)
        at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
        at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:747)
        at org.kohsuke.stapler.Stapler.invoke(Stapler.java:878)
        at org.kohsuke.stapler.Stapler.invoke(Stapler.java:676)
        at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:755)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1617)
[...]