1. Check the paper tray and ensure it is filled with the correct type of paper.

2. Ensure that your printer is set to double-sided in the printing preferences or settings.

3. Confirm that your document is correctly formatted to print double-sided. This can be done by viewing the print preview or checking your document settings for double-sided printing options.

4. Test the double-sided printing with a different document to ensure functionality.

5. Check for any jammed paper or other obstructions that might prevent the printer from double-sided printing.

6. Run a cleaning page from the printer’s settings, if this is supported.

7. Restart your printer to reset any temporary settings that may be interfering with your print job.

8. If the issue persists, check your printer’s manual or contact the manufacturer for troubleshooting instructions specific to your model.