Musk’s X Faces Probe in Europe Over Handling of Illegal Content, Disinformation

BRUSSELS—Elon Musk’s social-media platform X will face a formal probe in Europe over its handling of illegal content and disinformation in a first test of the European Union’s new online-content law.

The European Commission, the bloc’s executive arm, said Monday it opened a formal infringement proceeding against X, the platform formerly known as Twitter, under the Digital Services Act. The EU legislation, which took effect earlier this year, requires some of the world’s biggest online platforms to take steps to address illegal content and offer users a way to register complaints about the platforms’ moderation decisions, among other rules.