There is most likely an issue with the paper sensor in the paper tray.
Take a look around and see if you can detect any issues with the mechanics in that area. If you notice a broken lever or worn down roller then try to replace it with compatible parts. If the tray is removable then swap it out with a replacement.
Your printer has had a good ride if you made it last almost 8 years. Might be a good time to consider placing it to rest and treating yourself to some new hardware.