[20:10:50] Duel Links resolution must be 1280×720
but it is set to 1280 x 720
Hello, I also had the same problem as you. My monitor is wide and the scaling is set to 100%, however, DuelIt seemed to detect the screen as having the wrong resolution. I use Windows 10.
What I did to fix this was by right clicking on my desktop and clicked the ‘Display Setting’ option. I then clicked the ‘Advanced Display Setting’. I then changed my resolution screen from 1024 x 768 to 1280 x 720. Mind you, when you change the resolution setting this way, it will make your screen looks like it is zoomed out