S2721DGF, Xbox Series S, random black screen

Wondering if anyone else has the same problem? I replaced my old monitor with a new S2721DGF and I discovered the monitor would randomly black screen for 1 - 2 seconds. I also saw No HDMI signal message for 2-3 times. But I’m sure the connection is perfect.

I have not tested it for my PC yet as the monitor is mainly for my console gaming. I tried to use both Dell/Xbox original HDMI cables but it doesn’t help. My setting is 1440P/120hz. The problem even occurs when I’m in the Xbox main menu, not even gaming. So I wonder if this a defective item or software issue?