problem with oauth.access call

[UXnomaan]

I'm trying to set this up locally and I am getting the follow error and dump.

problem with oauth.access call

array (
  'ok' => false,
  'error' => 'http_failed',
  'code' => 0,
  'method' => 'CONNECT',
  'url' => 'https://slack.com/api/oauth.access',
  'info' => 
  array (
    'url' => 'https://slack.com/api/oauth.access',
    'content_type' => NULL,
    'http_code' => 0,
    'header_size' => 258,
    'request_size' => 138,
    'filetime' => -1,
    'ssl_verify_result' => 0,
    'redirect_count' => 0,
    'total_time' => 0.157,
    'namelookup_time' => 0.016,
    'connect_time' => 0.016,
    'pretransfer_time' => 0,
    'size_upload' => 0,
    'size_download' => 0,
    'speed_download' => 0,
    'speed_upload' => 0,
    'download_content_length' => -1,
    'upload_content_length' => -1,
    'starttransfer_time' => 0,
    'redirect_time' => 0,
    'redirect_url' => '',
    'primary_ip' => '168.147.252.40',
    'certinfo' => 
    array (
    ),
    'primary_port' => 80,
    'local_ip' => '10.172.77.110',
    'local_port' => 53586,
  ),
  'req_headers' => 
  array (
    '_request' => 'CONNECT slack.com:443 HTTP/1.1',
    'host' => 'slack.com:443',
    'proxy-authorization' => 'Basic bjAyMzU5MTg6QWhnaGFyMXU=',
    'proxy-connection' => 'Keep-Alive',
  ),
  'headers' => 
  array (
    '_status' => '',
  ),
  'body' => NULL,
)

any idea why this is happening?

Thanks.