Hi @Pierre-Yves Rosat ,
The documentation is mentioning usage of POST for createUploadSession, when I tested this in Postman even I have same problem 400 Bad request.
POST /sites/{siteId}/drive/items/{itemId}/createUploadSession
After testing it multiple times using PUT for createUploadSession is working.
PUT /sites/{siteId}/drive/items/{itemId}/createUploadSession
Hope this helps.
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