Text encoding for your CSV file needs to be UTF-8. Any non-ASCII characters will trigger a UTF-8 error and will have to be removed prior to uploading. This is typically the default choice for most spreadsheet programs — but not always. If you're prompted to select a format when using your spreadsheet program, be sure it's UTF-8.  If you receive this error, check your spreadsheet program and ensure that you're saving to the proper format.