Boundary timer Or intermediate timer

Hi,
I have a requirement like this: there are two tasks, A and B. If task B has not been processed after one day, a timeout notification needs to be sent, once per day. How can this be implemented using a timer in Flowable?
I tried using a boundary timer and an intermediate timer event. I found that the boundary timer can only execute once and proceeds to the service task (shown in the diagram as “msg”). As for the intermediate catch timer, after it loops three times, the delegate class corresponding to the service task fails to instantiate. The exception in act_ru_deadletter_job is:
“couldn’t instantiate class com.example.webadmin.workorder.listener.test.TestServiceTask”

The code for TestServiceTask is as follows:

@Slf4j
public class TestServiceTask implements JavaDelegate {
    @Override
    public void execute(DelegateExecution execution) {
        String taskId = execution.getCurrentActivityId();
        log.info("TestServiceTask  taskId:{}", taskId);
    }
}

here is workflow picture:

timeDuration is PT30S

How should I design the process to send timeout notifications at regular time intervals?

Please help