Troubleshooting - OKI Paper loaded on the indicated tray does not match selected paper size. Check the paper settings on the application and on the tray, and match the settings. 661: Tray 1, 662: Tray 2, 663: Tray 3, 664: Tray 4, 665: Tray 5 ... Inside of the machine, around the fuser unit. 370, 371, 373.