A Japanese court has blocked a Mongolia-based company’s bid to buy the Tokyo headquarters of the main pro-North Korea organization in Japan, Chongryon.

After months of screening, the Tokyo District Court announced on Thursday that due to purchase irregularities it would not allow the Ulan Bator-based Avar Limited Liability Company to purchase the property, which still serves as the headquarters for Japan’s main pro-North Korea organization.

The Mongolian firm, which had previously won an October 2013 auction for the building with a 5.01 billion yen (U.S. $48 million bid) bid, was rejected by the court because a certificate it submitted to