file_get_contents doesn't work on one particular server

Howdy all - We have a production server that runs our script fine. We're setting up a test server, and this particular script returns a length of zero: $ctx = stream_context_create(array('http' => array('timeout' => 1200))); // 20 minutes per file $contents = file_get_contents($full_url, 0, $ctx); You can paste the $full_url into a browser and it works fine (it's always a PDF document). It works fine with the same variables on the production server. Is there some configuration option that we've missed that's preventing it from working? Note that this is all https, and I did notice this difference in the phpinfo() but don't know if it's relevant: Production server: PHP 5.2.6 Registered PHP streams: php, file, data, http, ftp, compress.zlib, compress.bzip2, https, ftps, zip Test server: PHP 5.2.9-2 Registered PHP streams: php, file, data, http, ftp, compress.zlib