On December 23rd, players were unable to login to GT Sport servers, locking thousands of gamers out of GT Sport's online-only racing game.
Apparently, the surge in concurrent player count for GT Sport during the Christmas week triggered a false DDOS (Distributed Denial of Service) alarm at the PlayStation Network (PSN).
GT Sport servers rocked by player increase
The unexpected large network traffic in GT Sport on PSN was flagged and all further login attempts were blocked by the system.
４時間ぐらい前から北米のPSNチームの協力で復旧し始めています。たくさんのGTユーザーのトラフィックが、PSNへの攻撃と誤認されていたようです。
— 山内 一典 (@Kaz_Yamauchi) December 25, 2017
Polyphony's Kazunori Yamauchi sincerely apologizes for the inconvenience and has promised it would never happen again. Polyphony Digital took just over 24 hours to resolve the issue and players have been able to get back in the game.
Despite the lukewarm reviews from critics, it looks like sales of GT Sport have done really well with a surge in Christmas sales thanks to the recent 12 Days of Christmas promotion where PlayStation discounted some big titles in December.
Source: GT Planet