Internal server error for some reason

DLS has worked well for a long time. Yet now a problem called ‘internal server error’ occur when it is started. It seems like can be caused by various reasons. Following is my logs:

Starting Deep Learning Studio...

Checking GPU support…
GPU not supported
skipping cifar dataset download!
skipping IMDB dataset download!
skipping MNIST dataset download!
skipping reuters dataset download!
No changes detected
Using MXNet backend.
D:\DeepLearningStudio\conda3\lib\site-packages\allauth\account\templatetags\account_tags.py:4: DeprecationWarning: {% load account_tags %} is deprecated, use {% load account %}
DeprecationWarning)
D:\DeepLearningStudio\conda3\lib\site-packages\allauth\socialaccount\templatetags\socialaccount_tags.py:4: DeprecationWarning: {% load socialaccount_tags %} is deprecated, use {% load socialaccount %}
" {% load socialaccount %}", DeprecationWarning)
Operations to perform:
Apply all migrations: account, admin, auth, authtoken, automl, contenttypes, environments, project, projects, reversion, sessions, sites, socialaccount
Running migrations:
No migrations to apply.
Using MXNet backend.
D:\DeepLearningStudio\conda3\lib\site-packages\allauth\account\templatetags\account_tags.py:4: DeprecationWarning: {% load account_tags %} is deprecated, use {% load account %}
DeprecationWarning)
D:\DeepLearningStudio\conda3\lib\site-packages\allauth\socialaccount\templatetags\socialaccount_tags.py:4: DeprecationWarning: {% load socialaccount_tags %} is deprecated, use {% load socialaccount %}
" {% load socialaccount %}", DeprecationWarning)
Using MXNet backend.
d:\deeplearningstudio\conda3\lib\site-packages\notebook\services\kernels\kernelmanager.py:19: VisibleDeprecationWarning: zmq.eventloop.minitornado is deprecated in pyzmq 14.0 and will be removed.
Install tornado itself to use zmq with the tornado IOLoop.

from jupyter_client.session import Session
[I 17:28:10.611 LabApp] JupyterLab extension loaded from d:\deeplearningstudio\conda3\lib\site-packages\jupyterlab
[I 17:28:10.611 LabApp] JupyterLab application directory is d:\deeplearningstudio\conda3\share\jupyter\lab
[I 17:28:10.613 LabApp] Serving notebooks from local directory: D:\DeepLearningStudio\data\1
[I 17:28:10.613 LabApp] The Jupyter Notebook is running at:
[I 17:28:10.613 LabApp] http: / /127.0.0.1:8886/?token=…
[I 17:28:10.613 LabApp] or http: / /127.0.0.1:8886/?token=…
[I 17:28:10.613 LabApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
Using MXNet backend.

What’s the exact reason for that and how and i fix this? Any advise would be appreciated!