Court papers show the messaging platform did nothing when confronted with many reports of dangers to minors on the site.

Snapchat failed to act on “rampant” reports of child grooming, sextortion and other dangers to minors on its platform, according to a newly unredacted complaint against the company filed by New Mexico’s attorney general.

Youth-focused social-media company Snap grappled internally with how to warn users of its platform’s sextortion risks without striking fear in users and their ...