OAuth Exception : Invalid auth/bad request while uploading

Hello,

when I try requests like 'GET /materials/v1', 'GET /materials/$materialId/v1', 'GET /models/v1', 'GET /models/$modelId/v1' everything works fine but when I try to upload a model with a request like 'POST /models/v1' I get the following error:

A fatal error occurred during fetch exception
Exception : Invalid auth/bad request (got a 400, expected HTTP/1.1 20X or a redirect)

I am using the gitHub PHP-PECL scripts (copy-paste).

Does anyone knows where it could come from?