IllegalStateException when importing config data

[Centaur]

java.lang.IllegalStateException: UT000002: The response has already been started at io.undertow.server.HttpServerExchange.setStatusCode(HttpServerExchange.java:1353) at com.gtan.repox.admin.WebConfigHandler$.respondEmptyOK(WebConfigHandler.scala:70) at com.gtan.repox.admin.WebConfigHandler$$anonfun$setConfigAndRespond$1.apply(WebConfigHandl er.scala:46) at com.gtan.repox.admin.WebConfigHandler$$anonfun$setConfigAndRespond$1.apply(WebConfigHandl er.scala:44) at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32) at scala.concurrent.impl.ExecutionContextImpl$AdaptedForkJoinTask.exec(ExecutionContextImpl. scala:121) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.pollAndExecAll(ForkJoinPool.java:1253) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1346) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) 03-11 23:44:52.795 DEBUG c.gtan.repox.config.ConfigPersister akka://repox/user/ConfigPersister