Remote mac black screen after os update

ok, so i login to a friend mac from a pc for the last few months, he updated the os yesterday and we updated his teamviewer to latest version. I tried to get in yesterday but i get a black/grey screen, his desktop is there and he says he sees me moving the mouse but i see nothing.

Tried uninstalling and nothing, browsed a few things like the lock screen but my lock screen is grayed out so not sure if the new teamviewer isn't compatiable with the updated OS. He can login to my pc fine.

any help appreciated