Nifi HTTP ERROR 500

[#1]

I have problems in a nifi node, with the error that is below. I already removed it from the cluster and reinstalled it but it still keeps the error. 😞

HTTP ERROR 500

Problem accessing /nifi/. Reason:

    Server Error

Caused by:

javax.servlet.ServletException: org.apache.jasper.JasperException: java.lang.ClassNotFoundException: org.apache.jsp.WEB_002dINF.pages.canvas_jsp
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
	at org.eclipse.jetty.server.handler.gzip.GzipHandler.handle(GzipHandler.java:724)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:219)
	at org.eclipse.jetty.server.handler.HandlerList.handle(HandlerList.java:61)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:531)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce(EatWhatYouKill.java:132)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680)
	at java.lang.Thread.run(Thread.java:748)

Thanks. 

[#2]

@Gcima009 

It might be helpful to have more context around your issue.
What action and/or NiFi component are you using when the exception occurs/
What NiFi version are you using?
Can you share the entire error log from the nifi-app.log?

Thanks,

Matt

[#3]

Hi @MattWho i just kill the process that was using nifi in this particular node and then restarted the service.
That's all.

Thanks