The company behind the Fifa video games says it is investigating why some players’ personal information was exposed to other gamers.
Fans signing up for the new Fifa 20 Global Series found the online registration form was already filled in with other people’s information.
Popular online gaming live-streamers were among those who had their details exposed.
EA Sports, which publishes the game, apologised for the mistake.
“Player privacy and security are of the utmost importance to us, and we deeply apologise that our players encountered this issue today,” it said in a statement.
The error meant some players’ email addresses and birth dates were exposed to other gamers filling in the registration form.
The problem affected about 1,600 people, EA Sports said.
The company said it had found the “root cause” and was confident that players would not see the same mistake again.