由于业务原因，需要在群内发送通知消息，写完后不好使，请问是什么原因

public AjaxResult sendText(ImMessage imMessage) {
        Conversation conversation = new Conversation();
        conversation.setTarget(imMessage.getTarget());//目标群
        conversation.setType(ProtoConstants.ConversationType.ConversationType_Group);
        MessagePayload payload = new MessagePayload();
        payload.setType(1);
        payload.setSearchableContent("通知");
        //k是被通知的人，v是list 是通知的内容
        imMessage.getNotices().forEach((k, v) -> {
            v.forEach(item -> {
                payload.setPushContent(item);
                payload.setPushData("通知");
                //0 不提醒；1 对mentionedTargets里的user进行提醒；2 对群内所有人提醒。
                payload.setMentionedType(1);//@别人
                payload.setMentionedTarget(Collections.singletonList(k));//@ 的人
                // 发消息时固定使用admin用户
                TUser user = tUserService.selectTUserById(2L);
                try {
                    //发送消息
                    IMResult<SendMessageResult> resultSendMessage = MessageAdmin.sendMessage(user.getUid(), conversation, payload);
                    if (resultSendMessage == null || resultSendMessage.getErrorCode() != ErrorCode.ERROR_CODE_SUCCESS) {
                        throw new ServiceException("发送通知失败");
                    }
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            });
        });
        return AjaxResult.success();
    }