Caution message on my new Mac mini on startup "Make sure to use supplied input cables"

Own new Mac Mini. Using with LG 4K monitor. Using magic mouse snd keyboard. Get Square message that floats above the desktop on each and ever start up. mouse pointer will go under NOT onto message to close. Message is (caution ) Make sure to use supplied input cables. It has two options in square. 1 Do not display this message again 2. Close. Since You can not move to surface the choices are not available. I thought that the cables that came with my LG monitor were not adequate so I went on Amazon and bought the some expensive 8K cables that were suppose to work on anything. That did not resolve the problem.. I just want to remove this message and can't figure out how to do it. I don't want to remove all error notifications since I want to know when something is wrong.