Question marks instead of data are errors due to the encoding choice, i.e. there are no such characters in the key and therefore the system outputs question marks.
Most modern programs use UTF-8 encoding when saving files. For example, Google Sheets uses UTF-8 by default. However, if you are using Excel, you may need to check that you are using UTF-8 encoding. You can usually do this when you save your data in CSV.
You can do this by*:
*Please keep in mind that the steps may differ depending on the version of Excel you're using.
- When saving file select "Save As" and select ".CSV"
- Name your file
- At the bottom of this dialog box, select "Tools" and then "Web options"
- Head to the "Encoding" tab and in the "Save this document as:" dropdown, choose Unicode (UTF-8).
- Now you save your file.
The easiest tip to avoid errors is to always use UTF-8 encoding, then most likely your CSV file can be opened and read by most modern programs and spreadsheets.