The app says it is under maintenance
아직 한국어로 제공되지 않아 원문으로 표시됩니다. 위 메뉴에서 번역할 수 있습니다.
Then it is — that notice is put up deliberately while work is done, and it usually says when service is expected back. Nothing is wrong with your account or your installation, and reinstalling will not help.
Games already installed on your machine are unaffected by platform maintenance unless the game itself needs to reach the network to start.