Kicker un utilisateur génère une exception

Exception in thread "Thread-1" java.lang.NullPointerException: Cannot invoke "CommonClasses.Channel.getId()" because the return value of "CommonClasses.Subscription.getChannel()" is null at data.converters.SubscriptionConverter.converToEntity(SubscriptionConverter.java:37) at data.crud.SubscriptionCRUD.update(SubscriptionCRUD.java:164) at data.impl.ServerCommToServerDataImpl.removeFromUserList(ServerCommToServerDataImpl.java:448) at message.client.KickMemberClientMessage.handle(KickMemberClientMessage.java:31) at com.ClientListener.run(ClientListener.java:42)