MOB Games must certainly be a little spooked, and not by the monsters like Huggy Wuggy, Mommy Long Legs and Boxy Boo roaming the dark corners of Poppy's Toy Factory (and still preparing for the arrival of Poppy Playtime Chapter 3 next year). More to do with the huge reception to their recently released co-operative survival game, Project: Playtime.
As they commented on Twitter and via the game's Discord, the studio had to temporarily shut down the servers because they were overloaded, and quickly expanded their capacity to accommodate all the players. The servers were back up and running the following day.
According to SteamDB there were more than 100,000 concurrent players at the launch on 12 December. This figure has now dropped significantly (the daily peak remains stable at around 10,000 players).
On the other hand, just today a patch for the game was released</a> which fixes some bugs and fixes the matchmaking for Quick Matches. You can see the patch notes in the image below.