I bought my iPhone 11 today. Set it up, used it for a couple of hours. It was on idle for about 15-20 minutes. I pressed the power button couple of times, no response. Touched it to wake up pressed the power button again and my lock screen was there but instead of my wallpaper I saw a black screen.Then it went back to normal after a few seconds. (No response situation lasted about 10 seconds or so)Is it a hardware problem or a system-related glitch? I looked for the problem but people were generally telling that their phone wouldn’t open. My phone opened normally through the lock screen.