Lego has taken its online marketplace BrickLink offline after detecting what it described as unusual activity on the platform.
BrickLink is used by Lego collectors worldwide to buy and sell secondhand Lego sets, source new bricks and purchase limited edition releases.
It was originally set up by a fan, but Lego acquired it in 2019. In a homepage message, the firm said that before restoring BrickLink, it wanted to "fully understand" what had happened.
"That means containing the issue, investigating how it happened and checking for related issues," Lego said. It did not provide any further detail about whether the site has been breached or hacked, and whether any customer data was affected.
After being contacted by the BBC, Lego published the update.
BrickLink has been offline for the last three days, with a previous message saying it was down for maintenance.
Cyber-professional Melanie Hoskin has been collecting Lego for 45 years and is a regular user of BrickLink.
She told the BBC she had received multiple links for payment for a limited edition release she had pre-ordered on the platform, after she had already paid for it.
She said Lego did not believe that the payment had been taken and at one point said it would ban her from BrickLink.
