Actual conversation with a Samsung support specialist.
"HI my quick share isn't working from my samsung laptop to note 20"
"oh you'll have to call Microsoft for that"
"but isn't Quick Share a Samsung application?"
"Uhh I'm not sure about that..." 😑
You can still get the full experience of then just use usb to usb. You can access everything on your device quickly. If I am not near my usb cable i Bluetooth the files. Wifi direct back in the day used to be faster and worked. Not sure what quick share is supposed to be doing.
Unfortunately samsung support is awful. Anyways when you're in the Quick Share menu there should be a little "i" in the top right hand corner. It give tips about quick share, not sure if they'll work though. Sorry, can't think of anything else...
Maybe try turning your phone off for a few minutes then start it back up. My phone does the same thing sometimes it won't let me answer a call. Iv also had people try to call me nit doesn't ring or come up on calls missed. I have important medical issues and I need to be able to get all my calls my voice mail doesn't come on for the person calling! Very frustrating Samsung A11 sucks! Wouldn't buy it again!