Fatal error: Something went wrong while uploading the file. Empty file received. Maybe the file is too big, or you have no permissions to read it.
This happens WITHOUT the browser actually asking for any file to upload. (Tried Edge and Firefox.)
One then needs to actually log out and then log back in in order to see the "Reset Import" button to try again. Otherwise, it just fails instantly.
Does phpList actually work? I am using a Softaculus upload.