27ul850

I’m trying to connect my new ipad air 4 to my monitor lg 27ul850 using a oficial usb-c to ubs-c 6feet cable and is not working. Do i have to touch something on the monitor or in the ipad?

really dont know where to post this, so here i go buyed a 27ul850 as monitor for the next 6-7 years. have a macbook air connected to it and sometimes i play podcast or videos in youtube and change to use the other hdmi, where is connected the ps4, all normal but suddenly (20-30 after changing...