basic_training_container.ipynb failed CI

Link to the notebook:
https://github.com/aws/amazon-sagemaker-examples/blob/master/advanced_functionality/custom-training-containers/basic-training-container/notebook/basic_training_container.ipynb

Error:

---------------------------------------------------------------------------
Exception encountered at "In [8]":
---------------------------------------------------------------------------
Exception Traceback (most recent call last)
in
15 val_config = sagemaker.session.s3_input('s3://{0}/{1}/val/'.format(bucket, prefix), content_type='text/csv')
16
---> 17 est.fit({'train': train_config, 'validation': val_config })

/opt/conda/lib/python3.7/site-packages/sagemaker/estimator.py in fit(self, inputs, wait, logs, job_name, experiment_config)
667 self._prepare_for_training(job_name=job_name)
668
--> 669 self.latest_training_job = _TrainingJob.start_new(self, inputs, experiment_config)
670 self.jobs.append(self.latest_training_job)
671

[...]

Exception: Failed to run docker,images,-q,521695447989.dkr.ecr.us-west-2.amazonaws.com/sagemaker-training-containers/basic-training-container:latest

Open advanced_functionality/custom-training-containers/basic-training-container/notebook/basic_training_container.ipynb and start with cell In [8], where est.fit fails while running the training job. Reproduce the Docker error for the basic-training-container image and identify why the notebook's training step cannot run. Done means the notebook completes this step successfully in CI.

Written by the indexing model from the issue text.