upload file

I'm trying to upload a file using the url in a POST method. I receive the following error with both PDF,.doc and.docx:

<response uri="/recruit/private/xml/Candidates/uploadFile"><error><code>4424</code><message>Unable to process your request. Please verify whether you have provided proper file.</message></error></response>

I also tried using a bytearray in C# but I got the same result.

The API call i use is :

https://recruit.zoho.com/recruit/private/xml/Candidates/uploadFile?newFormat=1&authtoken=<auth token>&scope=recruitapi&version=2&id=<ID>&attachmentUrl=<url of the file>