{"errors":[{"message":"Bad Authentication data","code":215}]}

[matrixdevuk]

Hello.
I am currently developing a website, and I am trying to use twitter names to get an image…
Anyone know why I get:
{“errors”:[{“message”:“Bad Authentication data”,“code”:215}]}
When I use:

$size = "_bigger";
$api_call = "https://api.twitter.com/1.1/users/show.json?screen_name=matrixdevuk";
$results = json_decode(readfile($api_call));
return $results->profile_image_url;

[episod]

See [node:114] for details on how to use auth with your requests – API v1.1 requires that you authenticate each request.