✅ Microfiber Cloth I Use (Amazon paid link): br Disclosure: Some links above are affiliate links which means I may earn a small commission if you click and buy, at no extra cost to you.br br Ninja Support: br Ninja Double Oven (DCT451) stuck on “PRE” or preheating forever? This guide shows how to start preheat correctly, confirm the panel works, reset safely, check setup, wipe the control panel, and skip preheat on purpose plus when to contact support.