The European Commission on Friday said it found TikTok had not adequately protected children’s privacy rights on its platform by allowing adults to view the accounts of minors.

The action exposed children to cyberbullying, unwanted contact and predatory behavior, commission spokesperson Thomas Regnier said.

“Children’s content must never be visible to strangers,” he said. If TikTok does not take steps called for by the European Union’s landmark Digital Services Act, “minors are exposed to predators, to grooming and to cyberbullying,” Regnier said, adding that children aged 13 to 15 can “easily” change their accounts from private to public and the private accounts of minors aged 16 to 17 can be seen by anyone on the internet. “We do not accept this,” Regnier said. “Putting default settings for minors is not a beauty contest under the DSA. It must be effective.”

The investigation comes on the heels of back-to-back crackdowns on Big Tech by Brussels, which has led the world in regulating tech behemoths including Meta and Apple.

TikTok can now defend itself and reply to the findings. If unsatisfied with the Chinese firm’s response, the European Commission could issue a so-called non-compliance decision and possible fine worth up to 6% of the company’s total annual revenue.