### Apache Airflow version

2.4.2

### What happened

Create a DAG and set the schedule parameter using a CronTriggerTimeTable instance. Enable the DAG so that there is DAG run data. Try to access the Calendar View for the DAG. An ERR_EMPTY_RESPONSE error is displayed instead of the page.

The Calendar View is accessible for other DAGs  that are using the schedule_interval set to a cron string instead.

### What you think should happen instead

The Calendar View should have been displayed.

### How to reproduce

Create a DAG and set the schedule parameter to a CronTriggerTimeTable instance. Enable the DAG and allow some DAG runs to occur. Try to access the Calender View for the DAG.

### Operating System

Red Hat Enterprise Linux 8.6

### Versions of Apache Airflow Providers

_No response_

### Deployment

Virtualenv installation

### Deployment details

Airflow 2.4.2 installed via pip with Python3.9 to venv using constraints.

### Anything else

_No response_

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

)
        form = GraphForm(data=dt_nr_dr_data)
        form.execution_date.choices = dt_nr_dr_data["dr_choices"]
        task_instances = {
            ti.task_id: wwwutils.get_instance_with_map(ti, session)
            for ti in dag.get_task_instances(dttm, dttm)
        }
        tasks = {
            t.task_id: {
                "dag_id": t.dag_id,
                "task_type": t.task_type,
                "extra_links": t.extra_links,
                "is_mapped": isinstance(t, MappedOperator),
                "trigger_rule": t.trigger_rule,
            }
            for t in dag.tasks
        }
        if not tasks:
            flash("No tasks found", "error")
        session.commit()
        doc_md = wwwutils.wrapped_markdown(getattr(dag, "doc_md", None))
        task_log_reader = TaskLogReader()
        if task_log_reader.supports_external_link:
            external_log_name = task_log_reader.log_handler.log_name
        else:
            external_log_name = None
        state_priority = ["no_status" if p is None else p for p in wwwutils.priority]
        return self.render_template(
            "airflow/graph.html",
            dag=dag,