One of the world's largest cryptocurrency exchanges, Binance suspended all trading after system maintenance continued longer than expected.
The upgrades started around 7 pm ET Wednesday, when the Hong Kong-based exchange said users "may experience a decrease in exchange performance."
However, Binance announced last morning that maintenance was taking longer than expected due to "a significant increase in users and trading activity."
No transaction had been cleared by the exchange since 7:30 pm ET the website's trade history, showed.
According to CoinMarketCap, Binance is among the biggest and most heavily trafficked cryptocurrency exchanges, with around $480 million worth of bitcoin passing through its servers in the past 24 hours. It trails only OKEx in volume.
According to the company upgrades should be complete by 11 pm ET Thursday. It assured users that the issues were not related to a hack.
"We will allow a 30-minute window where users can cancel open orders prior to trading being opened," the exchange wrote. "We will continue to update every two hours until the upgrade is complete."
The exchange first posted on Twitter about the trading outage on Wednesday, and told users they may see some degraded performance for the duration.
But two hours later chief executive Changpeng Zhao announced that data had fallen out of sync due to a server issue. He added that the development team would need to re-sync from a master database. Zhao said in subsequent tweets that the maintenance did not proceed as planned, which led to the outage being prolonged.
The company's CEO, Changpeng "CZ" Zhao, explained the issues on Twitter. "We experienced a server issue on our replica database cluster, causing some data to be out of sync. Need to fully resync from master," he said. "Due the size of the data, it will take several hours. No data is lost. We appreciate your understanding and support."