Bending metal sound from oven @ box standard 425 degrees Fahrenheit

The Boss's sister, Aunt Boss, visited  recently from Alberta and suggested (paraphrased for satirical purposes) that with my continued slimming down with less sleep apnea symptoms, and my super-villain, man in black, Kingpin frame, that I should consider baking fish and food in the oven as opposed to frying on the stove. Okay, I thought, the Boss is an excellent cook, but I disliked baked boxed fish before, she made, but I would try it again, my way. Sure enough, Aunt Boss is correct, it works very well and tastes very good. So, the standard fish box states @ 425 degrees Fahrenheit for 20 minutes, but I have been grilling for 15 minutes. It has worked fine so far. But, today after church and shopping, while grilling, I heard a bending metal sound from the oven and the tray was bent, as I was grilling a vegetable. See above. I have now switched grilling temperature to 400 degrees Fahrenheit. The tray has had enough @425 degrees for 15 minutes.