title: All attempts to get a Google authentication bearer token failed, returning an empty token
body: <p>What I need help with / What I was wondering
  tfds.load failure</p>
  <pre class="lang-py prettyprint-override"><code>import tensorflow as tf
  import matplotlib.pyplot as plt
  import numpy as np
  import tensorflow as tf
  import tensorflow_datasets as tfds
  tfds.load('glue/sst2', download=True, try_gcs=True, split=&quot;validation&quot;)
  </code></pre>
  <pre><code>Stack trace
  2021-01-09 10:57:42.393771: E tensorflow/core/platform/cloud/curl_http_request.cc:614] The transmission of request 0x7fcf41a30f60 (URI: https://www.googleapis.com/oauth2/v4/token) has been stuck at 0 of 0 bytes for 61 seconds and will be aborted. CURL timing information: lookup time: 0.001158 (No error), connect time: 0 (No error), pre-transfer time: 0 (No error), start-transfer time: 0 (No error) 2021-01-09 10:57:42.397383: W tensorflow/core/platform/cloud/google_auth_provider.cc:184] All attempts to get a Google authentication bearer token failed, returning an empty token. Retrieving token from files failed with &quot;Unavailable: Error executing an HTTP request: libcurl code 42 meaning 'Operation was aborted by an application callback', error details: Callback aborted&quot;. Retrieving token from GCE failed with &quot;Failed precondition: Error executing an HTTP request: libcurl code 6 meaning 'Couldn't resolve host name', error details: Couldn't resolve host 'metadata'&quot;. 2021-01-09 10:58:46.099418: E tensorflow/core/platform/cloud/curl_http_request.cc:614] The transmission of request 0x7fcf3304b4e0 (URI: https://www.googleapis.com/storage/v1/b/tfds-data/o/datasets%2Fglue?fields=size%2Cgeneration%2Cupdated) has been stuck at 0 of 0 bytes for 61 seconds and will be aborted. CURL timing information: lookup time: 0.000995 (No error), connect time: 0 (No error), pre-transfer time: 0 (No error), start-transfer time: 0 (No error) 2021-01-09 11:00:01.098669: E tensorflow/core/platform/cloud/curl_http_request.cc:614] The transmission of request 0x7fcf3304b4e0 (URI: https://www.googleapis.com/storage/v1/b/tfds-data/o/datasets%2Fglue?fields=size%2Cgeneration%2Cupdated) has been stuck at 0 of 0 bytes for 61 seconds and will be aborted. CURL timing information: lookup time: 0.00099 (No error), connect time: 0 (No error), pre-transfer time: 0 (No error), start-transfer time: 0 (No error) 2021-01-09 11:02:05.646245: E tensorflow/core/platform/cloud/curl_http_request.cc:614] The transmission of request 0x7fcf33290910 (URI: https://www.googleapis.com/storage/v1/b/tfds-data/o/datasets%2Fglue?fields=size%2Cgeneration%2Cupdated) has been stuck at 0 of 0 bytes for 61 seconds and will be aborted. CURL timing information: lookup time: 0.001604 (No error), connect time: 0 (No error), pre-transfer time: 0 (No error), start-transfer time: 0 (No error)
  
  </code></pre>
  <p>What I've tried so far
  I use VPN, but It was useless at the time</p>
  <p>It would be nice if...
  Could we have done anything to make things better (documentation, etc.)?</p>
  <p>Environment information
  (if applicable)</p>
  <pre><code>Operating System: mac os 10.15.7
  Python version: 3.7.9
  tensorflow-datasets version: 4.2.0
  tensorflow version: 2.4.0
  tensorflow-metadata version: 0.26.0
  </code></pre>