The internet’s biggest recreation zone for kids is struggling to keep predators off its platform.

Louisiana AG Liz Murrill has filed a lawsuit against Roblox, accusing the gaming platform of enabling child exploitation and failing to protect young users.

The Roblox gaming platform, popular among cooped-up kids, is developing content ratings for games and improving parental controls after its successful public markets debut last month.

For years, the online platform Roblox has been a fascinating outlier in the debate over digital regulation — a cute, customizable universe filled with kids solving puzzles and jumping through ...