Error while executng job from knime web portal :There was an issue loading the PageBuilder from the server.

[knimeadmin_asa]

Knime log :
2023-10-31 17:50:25,754 : WARN : pool-1-thread-11 : abb7fb8a-0edc-4754-b882-305befa94c22 : JsonRpcErrorResolver : : : A json rpc error occurred
java.lang.NullPointerException
at org.knime.core.util.FileUtil.looksLikeUNC(FileUtil.java:1232)
at org.knime.core.util.FileUtil.resolveToPath(FileUtil.java:1201)
at com.knime.gateway.impl.webportal.service.DefaultWizardExecutionService.collectWebResourceUrlsFromConfigElement(DefaultWizardExecutionService.java:586)
at com.knime.gateway.impl.webportal.service.DefaultWizardExecutionService.collectWebResourceUrls(DefaultWizardExecutionService.java:567)
at com.knime.gateway.impl.webportal.service.DefaultWizardExecutionService.ensureThatWebResourceUrlsAreAvailable(DefaultWizardExecutionService.java:540)
at com.knime.gateway.impl.webportal.service.DefaultWizardExecutionService.getWebResource(DefaultWizardExecutionService.java:632)
at com.knime.gateway.impl.webportal.jsonrpc.service.JsonRpcWizardExecutionServiceWrapper.getWebResource(JsonRpcWizardExecutionServiceWrapper.java:101)
at jdk.internal.reflect.GeneratedMethodAccessor139.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at com.googlecode.jsonrpc4j.JsonRpcBasicServer.invoke(JsonRpcBasicServer.java:478)
at com.googlecode.jsonrpc4j.JsonRpcBasicServer.handleObject(JsonRpcBasicServer.java:349)
at com.googlecode.jsonrpc4j.JsonRpcBasicServer.handleJsonNodeRequest(JsonRpcBasicServer.java:274)
at com.googlecode.jsonrpc4j.JsonRpcBasicServer.handleRequest(JsonRpcBasicServer.java:242)
at org.knime.gateway.impl.jsonrpc.JsonRpcRequestHandler.handle(JsonRpcRequestHandler.java:103)
at com.knime.gateway.executor.jsonrpc.JsonRpcServerRequestHandler.handle(JsonRpcServerRequestHandler.java:77)
at com.knime.enterprise.executor.genericmsg.GenericServerRequestManager.forwardRequest(GenericServerRequestManager.java:82)
at com.knime.enterprise.executor.amqp.actions.GenericServerRequestTask.perform(GenericServerRequestTask.java:66)
at com.knime.enterprise.executor.amqp.RabbitMQMessageConsumer$Consumer.processMessage(RabbitMQMessageConsumer.java:133)
at com.knime.enterprise.executor.amqp.RabbitMQMessageConsumer$Consumer.handleDelivery(RabbitMQMessageConsumer.java:107)
at com.rabbitmq.client.impl.ConsumerDispatcher$5.run(ConsumerDispatcher.java:149)
at com.rabbitmq.client.impl.ConsumerWorkService$WorkPoolRunnable.run(ConsumerWorkService.java:104)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.base/java.lang.Thread.run(Unknown Source)
2023-10-31 17:50:30,196 : WARN : pool-1-thread-14 : abb7fb8a-0edc-4754-b882-305befa94c22 : JsonRpcErrorResolver : : : A json rpc error occurred
java.lang.NullPointerException

Can anyone please guide ho wto resolve this issue?

[AlexanderFillbrunn]

Hi,
Is there a proxy or application load balancer in front of the server? I haven’t seen this error before, but it looks weird that it has trouble with the mime types, probably coming from the content-type header. In the Server’s Tomcat access log you can check if you find lines with a 500 in the second to last column. If those are there, at least some of the errors in your browser’s console come from the server directly. If not, some system in-between is causing the issues.
Kind regards,
Alexander

[knimeadmin_asa]

Hi Alexander,
Thanks for understanding my query and for your suggestion
Just FYI i have checked the Tomcats access log file and couldnt find any line line with 500.
So can you suggest any alternative which would helpful for me to rectify this issue.
Thanks

[AlexanderFillbrunn]

Hi,
Unfortunately this is where I can’t help without knowing your environment. If the 500 does not come from the KNIME Server, it most likely comes from some network component in-between the client (your browser) and the server. This would most likely be a load balancer or a proxy. You’d need to check the logs of those systems to find out what is happening.
Kind regards,
Alexander