Sort string format

https://developers.pipedrive.com/docs/api/v1/#!/Organizations/get_organizations_id_files

Hello I’m trying to list files for an organization: https://xx.pipedrive.com/v1/organizations/id/files?sort=file_name+ASC&api_token=token

but the data doesn’t get sorted it’s the same if i use sort=file_name%20ASC, what am I doing wrong?