Call of Duty: Warzone 2 has a bug that is locking players out of the free-to-play game unless they purchase Call of Duty: Modern Warfare II. This is slightly confusing: Warzone 2 and Modern Warfare 2 share the same client launcher, but are distinct products, and players should be able to download Warzone 2 and play it without having purchased Modern Warfare 2.
The problem appears to be widespread, and in most cases seems to occur after players have played several matches and try to start another from the menus. At this point a pop-up window appears saying "Purchase Modern Warfare 2 to have access to everything" and the game won't start. This appears to be happening across several playlists, and restarting the game doesn't help.
"Since yesterday I played probably around 6 Warzone 2.0 matches with no problem (finished my last match a few minutes ago)," wrote Unf0cused. "Now when I try to play it, when I click Battle Royale Solos I get the "Purchase Modern Warfare II to have access to everything" window (I've also tried the other BR variants with the same result)."
Players have been able to work out ways around certain Warzone 2 glitches like the social feed not working (which is now fixed) but this appears to be a hard block at the moment. It is certainly unintentional, because it has also been locking out players who have already purchased Modern Warfare 2.
The Warzone 2 trello board contains no mention of this particular glitch, though it does note that the 'play again' button has been temporarily disabled which may have something to do with it, nor has there been any acknowledgement from other official channels. Warzone 2 just pushed a patch live for a bug that was preventing players from partying up, so it looks like the fix may have had unintended consequences.