Error API Upload "Failed User authentication"

I have trie to upload the presentation in .ppt or other format to SlideShare app from my web application written in ASP.net (C#) but when using API upload_slideshow (or api 1.0 or 2.0) the following error returns "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<slideshareserviceerror>\n <message>2:Failed User authentication</message>\n</slideshareserviceerror>".

Premise
I use the other functions API of slideshare correctly by entering the correct credentials and generating the hash as required.

Please, Help me!!