title: python boto3 connection error with no apparent cause
body: <p>I'm hitting an error with code that connects to AWS using boto3. The error just started yesterday afternoon, and between the last time I didn't get the error and the first time I got the error I don't see anything that changed.</p>
  
  <p>The error is:</p>
  
  <pre><code>botocore.exceptions.EndpointConnectionError: Could not connect to the endpoint URL:
  </code></pre>
  
  <p>In .aws/config I have:</p>
  
  <pre><code>$ cat ~/.aws/config
  [default]
  region=us-east-1
  </code></pre>
  
  <p>Here's what I know:</p>
  
  <ul>
  <li>Using the same AWS credentials and config on another machine, I don't see the error.</li>
  <li>Using different AWS credentials and config on the same machine, I do see the error.</li>
  <li>I'm the only one in our group that has this issue for any credentials on any machine.</li>
  </ul>
  
  <p>I don't think I changed anything that would affect this between the last time this worked and the first time it didn't. It seems like I'd have had to change some AWS specific configuration on my side or some low level libraries, and I didn't make any such change. I was talking with a colleague for 30-45 minutes and when I returned and picked up where I left off the issue first appeared.</p>
  
  <p>Any thoughts or ideas on troubleshooting this?</p>
  
  <p>Full exception dump follows.</p>
  
  <pre><code>$ python
  Python 2.7.10 (default, Jul 14 2015, 19:46:27) 
  [GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import boto3
  &gt;&gt;&gt; boto3.client('ec2').describe_regions()
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/Library/Python/2.7/site-packages/botocore/client.py", line 200, in _api_call
      return self._make_api_call(operation_name, kwargs)
    File "/Library/Python/2.7/site-packages/botocore/client.py", line 244, in _make_api_call
      operation_model, request_dict)
    File "/Library/Python/2.7/site-packages/botocore/endpoint.py", line 173, in make_request
      return self._send_request(request_dict, operation_model)
    File "/Library/Python/2.7/site-packages/botocore/endpoint.py", line 203, in _send_request
      success_response, exception):
    File "/Library/Python/2.7/site-packages/botocore/endpoint.py", line 267, in _needs_retry
      caught_exception=caught_exception)
    File "/Library/Python/2.7/site-packages/botocore/hooks.py", line 226, in emit
      return self._emit(event_name, kwargs)
    File "/Library/Python/2.7/site-packages/botocore/hooks.py", line 209, in _emit
      response = handler(**kwargs)
    File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 183, in __call__
      if self._checker(attempts, response, caught_exception):
    File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 250, in __call__
      caught_exception)
    File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 273, in _should_retry
      return self._checker(attempt_number, response, caught_exception)
    File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 313, in __call__
      caught_exception)
    File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 222, in __call__
      return self._check_caught_exception(attempt_number, caught_exception)
    File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 355, in _check_caught_exception
      raise caught_exception
  botocore.exceptions.EndpointConnectionError: Could not connect to the endpoint URL: "https://ec2.us-east-1.amazonaws.com/"
  </code></pre>