Binance, the world’s largest cryptocurrency exchange by trading volume, suspended trading on Wednesday for more than six hours for “system maintenance.”

The exchange, which has offices and corporate registrations in Malta, Seychelles, the Cayman Islands and elsewhere, resumed trading around 5:30 p.m. UTC (12:30 p.m. Eastern time), according to a notice on its website.

The exchange had alerted users earlier in the day that it suspended all deposits, withdrawals, spot trading, margin trading, person-to-person trading, lending, redemption and asset transfers from sub-accounts, margin accounts, futures accounts and wallets that hold government-issued or “fiat” currencies. Futures trading was unaffected, the exchange said.

During the Binance outage, rival cryptocurrency exchanges saw big jumps in trading orders, based on data from the website Coin360. According to the site, transaction volumes over the 24 hours through 12:36 p.m. ET jumped more than 50 percent on the Malta-based exchange OKEx and on London-based Bitstamp. Binance’s 24-hour volume dropped by 31 percent during the period.

OKEx and Bitstamp saw trading volumes surge during Binance's outage. Source: Coin360 Source: Coin360

Josh Goodbody, Binance’s London-based director for growth and international business, told CoinDesk in a series of WhatsApp messages that there was an “issue with an engine that pushed data around the system.”

“It was a simple systems messaging error that we wanted to fix straightaway,” Goodbody said. “Main effect was balances were slow to update.”

It’s “definitely untrue” that the exchange suffered an internal hack, he said, referring to some posts on social media.

Binance CEO Changpeng “CZ” Zhao tweeted “all systems back to normal” at 12:57 p.m. New York time.

Hours earlier, Zhao tweeted that the exchange would “waive everyone’s margin interests for today.”