Can you please tell me, after executing this also I am not getting proper response.
MY script
$cmd="curl https://api.box.com/oauth2/token \ -d 'grant_type=refresh_token&refresh_token=uuuuuuuuu&client_id=uuuuuuu&client_secret=uuuuuuu' \ -X POST"; exec($cmd,$result);
response
Array ( [0] => {"error":"invalid_request","error_description":"Invalid grant_type parameter or parameter missing"} )