Just something from my experience:
Wanted to flag this in case it helps anyone in the future.
I’m on an R3. I was on DumaOS 4.0.1510, app 4.0.290. On October 2, around 11:10–11:30 PM EDT, Black Ops 7 matchmaking broke. Ranked and multiplayer had both been fine earlier that night.
Ranked died right away. Lobby Not Found, error cause 10, error code 2029. Multiplayer was slow to find a game at first, then worked again around 25 ms ping (usually I'm around 7-11 ms). Ranked never came back.
I was queuing alone on Battle.net, wired into the R3, on fiber, with NAT Open. Account is not banned. Geo-Filter was off, and I hadn’t changed any in-game settings.
I tried the usual stuff. Scan and repair, flush DNS, renew the adapter, power-cycle the ONT and the R3, terminate/repair/reset the game, and a full uninstall and reinstall. I also launched the same game through the Xbox app instead of Battle.net, and I joined a friend’s party. Ranked still failed every time.
Plugging the PC straight into the fiber ONT and skipping the R3 let Ranked queue normally, so I assumed it was the router.
Downgrading to 4.0.540 by itself did not fix it. A factory reset after that did. Ranked has been fine since. Not sure if the reset cleared something left over from 4.0.1510, or if the reset itself was what fixed it.
Happy to share the Activision support notes if you want them. Not much in them other than the Support agent telling me to do some basic troubleshooting.
