2006 Dell monitor shows picture but still says “Cannot display this video mode” on Xbox Series S

I’m using an old Dell monitor from around 2006. I have it connected to my Xbox Series S and it does show the picture, but the monitor keeps displaying this message on top of the screen:

So even though I can see the Xbox image, the error message never goes away. I’m guessing the Xbox resolution or refresh rate isn’t fully compatible with the monitor.

Is there a way to:

• Force the Xbox Series S to output 1024x768 at 60Hz, or
• Get rid of this error message permanently?

I’m using HDMI with an adapter.
Any help would be appreciated.