turbaszek opened a new issue #11060:
URL: https://github.com/apache/airflow/issues/11060
**Apache Airflow version**:
Master branch.
**Environment**:
```
./breeze --python 3.7 --backend postgres --db-reset restart
```
**What happened**:
Webserver returned this error:
```
Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 2447, in
wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1952, in
full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1821, in
handle_user_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 39,
in reraise
raise value
File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1950, in
full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1936, in
dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/opt/airflow/airflow/www/decorators.py", line 126, in wrapper
return f(self, *args, **kwargs)
File
"/usr/local/lib/python3.7/site-packages/flask_appbuilder/security/decorators.py",
line 109, in wraps
return f(self, *args, **kwargs)
File "/opt/airflow/airflow/www/decorators.py", line 61, in wrapper
return f(*args, **kwargs)
File "/opt/airflow/airflow/utils/session.py", line 65, in wrapper
return func(*args, **kwargs)
File "/opt/airflow/airflow/www/views.py", line 2119, in refresh
dag = current_app.dag_bag.get_dag(dag_id)
File "/opt/airflow/airflow/models/dagbag.py", line 191, in get_dag
is_expired = (orm_dag.last_expired and dag.last_loaded <
orm_dag.last_expired)
AttributeError: 'NoneType' object has no attribute 'last_loaded'
```
**What you expected to happen**:
To see no error but DAG view.
**How to reproduce it**:
```shell
./breeze --python 3.7 --backend postgres --db-reset restart
# then
export AIRFLOW__CORE__DAGS_FOLDER=airflow/providers/google/cloud/example_dags
airflow scheduler -D
airflow webserver -w 1 -D
```
Create a user, go to webserver, turn on `example_gcp_dataproc` and trigger
it.
After few seconds you should see a nuclear cloud under this address:
`http://0.0.0.0:28080/refresh?dag_id=example_gcp_dataproc`
**Anything else we need to know**:
N/A
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