abp v6.0(ts)+.net core(3.0) 发布通知前端abp.notifications.received不进入

[ztwz]

Startup.cs中
//这个和发布通知无关吧？
app.UseEndpoints(endpoints =>
{
endpoints.MapHub<MessageHub>("/MessageHub");

});

领域层后端发布代码

    public class NotificationAppService: BusinessAssistantAppServiceBase,INotificationAppService, ITransientDependency
    {
        private readonly INotificationPublisher _notiticationPublisher;

        public NotificationAppService(INotificationPublisher  notificationPublisher)
        {
            _notiticationPublisher = notificationPublisher;
        }

        //发送常规通知给用户
        public async Task Publish_SentFrendshipRequest(string senderUserName, string friendshipMessage)
        {
            await _notiticationPublisher.PublishAsync("SentFrendshipRequest",
                new SentFrendshipRequestNotificationData(senderUserName, friendshipMessage),
                userIds: new[] { new Abp.UserIdentifier(null, 3), new Abp.UserIdentifier(1, 2), new Abp.UserIdentifier(1, 1) }, severity: NotificationSeverity.Success);

        }

    }

前端Vue监听代码 main.vue

init () {
        util.abp.event.on('abp.notifications.received', function (userNotification) {
            console.log(userNotification);
          });
}

后端发布通知，前端abp.event.on监听的全局事件abp.notifications.received并不会进入，不知道问题出在哪，请指点一下，谢谢。