How to solve conflict folder error with Dropbox API

I am using Dropbox API explorer to test the upload of a file before usign the code. I am getting an error when in my opinion all the params are right.

request:

		curl -X POST https://content.dropboxapi.com/2/files/upload \
		  --header 'Authorization: Bearer aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' \
		  --header 'Content-Type: application/octet-stream' \
		  --header 'Dropbox-API-Arg: {"path":"/my/folder/","property_groups":[]}' \
		  --data-binary @'myspreadsheet.xlsx'

response:

{
	"error_summary": "path/conflict/folader/..",
	"error": {
		".tag": "path",
		"reason": {
			".tag": "conflict",
			"conflict": {
				".tag": "folder"
			}
		},
		"upload_session_id": "AAAAAAAABAAAAAAAA"
	}
}

When I send a request to `https://dropbox.github.io/dropbox-api-v2-explorer/#files_list_folder` I get the path to 

/my/folder

 in the response, which is EMPTY by the way. Can anyone help?