I am using PHP Curl extension for a project which requires uploading file to a server I had no control over. However, I was getting HTTP Status 417 with error message Expectation Failed. I don’t know what this is supposed to do and why curl sends it, so I tried removing it by overriding it with the following code:
curl_setopt($curl,CURLOPT_HTTPHEADER,array("Expect: "));
It worked and the file uploaded successfully.
Hope this helps.