Error when uploading through proxy

I am getting the below error when i try to upload a image . I have the proxy configured in StreamWrapper.php and S3client.php .. My site is able to make a connection to S3 bucket behind proxy and when i try to upload a image. The image got uploaded in S3 bucket and fails at the below request.

$config['request.options'] = array('proxy' => 'ipaddress');

Error-
Guzzle\Common\Exception\RuntimeException: Error creating resource. [message] fopen(https://*********.s3.amazonaws.com/Lighthouse_2.jpg): failed to open stream: Unable to find the socket transport "http" - did you forget to enable it when you configured PHP?
[file] .../sites/all/vendor/guzzle/guzzle/src/Guzzle/Stream/PhpStreamRequestFactory.php
[line] 217 in Guzzle\Stream\PhpStreamRequestFactory->createResource() (line 279 of /...../sites/all/vendor/guzzle/guzzle/src/Guzzle/Stream/PhpStreamRequestFactory.php).
The website encountered an unexpected error. Please try again later.

Thanks in advance.