Tensorboard not working following the documentation.

Following this documentation here.

https://docs.microsoft.com/en-us/azure/machine-learning/how-to-monitor-tensorboard

I have followed all the steps exactly as documented. But whenever I run tb.start() I do get an endpoint URL, but it always gives me a "502 Bad Gateway" error.

I see a similar issue was raised here.

[#920](https://github.com/Azure/MachineLearningNotebooks/issues/920)

Although the answer wasn't helpful as it just pointed back to the documentation which I was already trying, and failing to get working

Start by reproducing tb.start() from the linked Azure Machine Learning TensorBoard documentation and compare its behavior with issue #920. Done means the returned endpoint loads TensorBoard instead of returning a 502 Bad Gateway, with the reproduction details captured for verification.

Escrita pelo modelo de indexação a partir do texto da issue.