Spark job-server scala.MatchError while submitting WordCountExample

Question

When I submit a job to the Spark job-server, I can see that the Spark context is created. However, there is an error in WebApi.getJobManagerForContext method:

[2018-06-11 07:05:24,495] INFO ocalContextSupervisorActor [] [] - SparkContext 9f3d1f60-spark.jobserver.WordCountExample initialized {
"status": "ERROR", "result": { "message": "(Actor[akka://JobServer/user/context-supervisor/9f3d1f60-spark.jobserver.WordCountExample#-1687191062],Actor[akka://JobServer/user/context-supervisor/global-result-actor#1953406985]) (of class scala.Tuple2)", "errorClass": "scala.MatchError", "stack": "scala.MatchError: (Actor[akka://JobServer/user/context-supervisor/9f3d1f60-spark.jobserver.WordCountExample#-1687191062],Actor[akka://JobServer/user/context-supervisor/global-result-actor#1953406985]) (of class scala.Tuple2) at spark.jobserver.WebApi.spark$jobserver$WebApi$$getJobManagerForContext(WebApi.scala:728) at spark.jobserver.WebApi$$anonfun$jobRoutes$1$$anonfun$apply$75$$anonfun$apply$76.apply(WebApi.scala:640) at spark.jobserver.WebApi$$anonfun$jobRoutes$1$$anonfun$apply$75$$anonfun$apply$76.apply(WebApi.scala:630) at spray.routing.ApplyConverterInstances$$anon$17$$anonfun$apply$6.apply(ApplyConverterInstances.scala:60) at spray.routing.ApplyConverterInstances$$anon$17$$anonfun$apply$6.apply(ApplyConverterInstances.scala:59) at spray.routing.ConjunctionMagnet$$anon$3$$anon$4$$anonfun$happly$1$$anonfun$apply$1.apply(Directive.scala:38) at spray.routing.ConjunctionMagnet$$anon$3$$anon$4$$anonfun$happly$1$$anonfun$apply$1.apply(Directive.scala:37) at spray.routing.directives.BasicDirectives$$anon$2.happly(BasicDirectives.scala:79) at spray.routing.Directive$$anon$7$$anonfun$happly$4.apply(Directive.scala:86) at spray.routing.Directive$$anon$7$$anonfun$happly$4.apply(Directive.scala:86) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30) at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30) at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1$$anonfun$apply$1.apply(RouteConcatenation.scala:32) at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1$$anonfun$apply$1.apply(RouteConcatenation.scala:31) at spray.routing.RequestContext$$anonfun$withRejectionHandling$1.applyOrElse(RequestContext.scala:130) at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:36) at spray.routing.RequestContext$$anon$1.handle(RequestContext.scala:84) at akka.spray.UnregisteredActorRefBase.$bang(UnregisteredActorRefBase.scala:72) at spray.routing.RequestContext$$anon$3.handle(RequestContext.scala:102) at akka.spray.UnregisteredActorRefBase.$bang(UnregisteredActorRefBase.scala:72) at spray.routing.RequestContext.reject(RequestContext.scala:202) at spray.routing.directives.RouteDirectives$$anon$1.apply(RouteDirectives.scala:35) at spray.routing.directives.RouteDirectives$$anon$1.apply(RouteDirectives.scala:34) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92) at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1$$anonfun$apply$1.apply(RouteConcatenation.scala:32) at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1$$anonfun$apply$1.apply(RouteConcatenation.scala:31) at spray.routing.RequestContext$$anonfun$withRejectionHandling$1.applyOrElse(RequestContext.scala:130) at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:36) at spray.routing.RequestContext$$anon$1.handle(RequestContext.scala:84) at akka.spray.UnregisteredActorRefBase.$bang(UnregisteredActorRefBase.scala:72) at spray.routing.RequestContext$$anon$3.handle(RequestContext.scala:102) at akka.spray.UnregisteredActorRefBase.$bang(UnregisteredActorRefBase.scala:72) at spray.routing.RequestContext.reject(RequestContext.scala:202) at spray.routing.directives.RouteDirectives$$anon$1.apply(RouteDirectives.scala:35) at spray.routing.directives.RouteDirectives$$anon$1.apply(RouteDirectives.scala:34)" }