Mei has been removed from the game (lol) until November 17, so Practice Range runs for "All Heroes" and "Damage Only" won't be accepted until then. All other practice range categories are fine.

Here is the original blue post: https://us.forums.blizzard.com/en/overwatch/t/mei-disabled-through-november-15/739017

And here's the updated blue post from Nov 15: https://us.forums.blizzard.com/en/overwatch/t/regarding-our-mid-season-cycle-patch/748128