Getting Error messages java.lang.NoClassDefFoundError

[Keylane ICT]

Getting an error message when transitioning between status. These statuses has a validator using scriptrunner and upon disabling the validator, the transition is then possible. I was wondering if anyone has any idea on what is causing this? It is puzzling me at the moment. 

java.lang.NoClassDefFoundError: org/codehaus/groovy/runtime/ExceptionUtils
    	at groovy.lang.Closure.call(Closure.java:420) [?:?]
    	at org.codehaus.groovy.runtime.ConvertedClosure.invokeCustom(ConvertedClosure.java:54) [?:?]
    	at org.codehaus.groovy.runtime.ConversionHandler.invoke(ConversionHandler.java:124) [?:?]
    	at com.sun.proxy.$Proxy3665.handle(Unknown Source) [?:?]
    	at com.onresolve.scriptrunner.runner.diag.DiagnosticsErrorHandler$handle.call(Unknown Source) [?:?]
    	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callSafe(AbstractCallSite.java:90) [?:?]
    	at com.onresolve.scriptrunner.runner.diag.DiagnosticsManagerImpl$DiagnosticsExecutionHandlerImpl.execute(DiagnosticsManagerImpl.groovy:317) [?:?]
    	at com.onresolve.scriptrunner.runner.diag.DiagnosticsExecutionHandler$execute$3.call(Unknown Source) [?:?]
    	at com.onresolve.scriptrunner.jira.workflow.AbstractScriptWorkflowFunction.run(AbstractScriptWorkflowFunction.groovy:86) [?:?]
    	at com.onresolve.scriptrunner.jira.workflow.AbstractScriptWorkflowFunction$run$0.callCurrent(Unknown Source) [?:?]
    	at com.onresolve.jira.groovy.GroovyValidator.validate(GroovyValidator.groovy:32) [?:?]
    	at com.atlassian.jira.workflow.SkippableValidator.validate(SkippableValidator.java:45) [classes/:?]
    	at com.opensymphony.workflow.AbstractWorkflow.verifyInputs(AbstractWorkflow.java:1466) [osworkflow-2.9.0-atlassian-1.jar:2.9.0-atlassian-1]
    	at com.opensymphony.workflow.AbstractWorkflow.transitionWorkflow(AbstractWorkflow.java:1167) [osworkflow-2.9.0-atlassian-1.jar:2.9.0-atlassian-1]
    	at com.opensymphony.workflow.AbstractWorkflow.doAction(AbstractWorkflow.java:557) [osworkflow-2.9.0-atlassian-1.jar:2.9.0-atlassian-1]
    	at com.atlassian.jira.workflow.OSWorkflowManager.doWorkflowActionInsideTxn(OSWorkflowManager.java:830) [classes/:?]
    	at com.atlassian.jira.workflow.OSWorkflowManager.doWorkflowAction(OSWorkflowManager.java:787) [classes/:?]
    	at com.atlassian.jira.bc.issue.DefaultIssueService.transition(DefaultIssueService.java:492) [classes/:?]
    	at com.atlassian.jira.web.action.issue.CommentAssignIssue.doExecute(CommentAssignIssue.java:161) [classes/:?]
    	at webwork.action.ActionSupport.execute(ActionSupport.java:165) [webwork-1.4-atlassian-30.jar:?]
    	at com.atlassian.jira.action.JiraActionSupport.execute(JiraActionSupport.java:63) [jira-api-7.13.12.jar:?]
    	at webwork.interceptor.DefaultInterceptorChain.proceed(DefaultInterceptorChain.java:39) [webwork-1.4-atlassian-30.jar:?]
    	at webwork.interceptor.NestedInterceptorChain.proceed(NestedInterceptorChain.java:31) [webwork-1.4-atlassian-30.jar:?]
    	at webwork.interceptor.ChainedInterceptor.intercept(ChainedInterceptor.java:16) [webwork-1.4-atlassian-30.jar:?]
    	at webwork.interceptor.DefaultInterceptorChain.proceed(DefaultInterceptorChain.java:35) [webwork-1.4-atlassian-30.jar:?]
    	at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:225) [webwork-1.4-atlassian-30.jar:?]
    	at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:154) [webwork-1.4-atlassian-30.jar:?]
    	at com.atlassian.jira.web.dispatcher.JiraWebworkActionDispatcher.service(JiraWebworkActionDispatcher.java:138) [classes/:?]
    	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [servlet-api.jar:?]
    	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [catalina.jar:8.5.35]
    	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina.jar:8.5.35]
    	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-websocket.jar:8.5.35]
    	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina.jar:8.5.35]
    	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina.jar:8.5.35]
    	at com.atlassian.jira.web.filters.JiraLastFilter.lambda$doFilter$0(JiraLastFilter.java:39) [classes/:?]
    	at com.atlassian.jira.web.filters.steps.ChainedFilterStepRunner.doFilter(ChainedFilterStepRunner.java:74) [classes/:?]
    	at com.atlassian.jira.web.filters.JiraLastFilter.doFilter(JiraLastFilter.java:36) [classes/:?]
    	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina.jar:8.5.35]
    	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina.jar:8.5.35]
    	at com.atlassian.core.filters.HeaderSanitisingFilter.doFilter(HeaderSanitisingFilter.java:37) [atlassian-core-5.0.9.jar:?]
    	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina.jar:8.5.35]
    	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina.jar:8.5.35]