Coinbase says at 11:11 a.m. ET that "all buys and sells have been temporarily disabled."
The interruption in service comes as bitcoin briefly tumbled below $11,000, down 44 percent from its record high hit Sunday.
On Thursday, Coinbase had temporarily disabled buys and sells at 5:57 p.m. ET, according to its status website. The issue was resolved within 15 minutes.
Coinbase, one of the biggest bitcoin marketplaces in the U.S., said Friday that trading was up again after being down for more than two hours amid a price rout in cryptocurrencies.
"Buys and sells have been re-enabled. We are monitoring for stability," Coinbase said on its status website as of 1:44 p.m., ET.
Earlier, the company said that buying and selling was temporarily disabled.
Bitcoin traded about 18 percent lower near $12,800 on Coinbase as of 11:39 a.m. ET. Earlier, the digital currency had fallen as low as $10,400, down 44 percent from its record high hit Sunday.
Coinbase's mobile app, one of the most popular overall applications in the Apple App store this month, is a leading way in the U.S. to buy and sell major digital currencies bitcoin, ethereum and litecoin. The company added trading for bitcoin's offshoot bitcoin cash in a rocky rollout this week.
On Thursday, Coinbase had temporarily disabled trading at 5:57 p.m. ET, according to its status website. The issue was resolved within 15 minutes.
Coinbase has struggled in recent months to keep up with high demand. On Dec. 12, the company temporarily suspended buys and sells of ethereum twice in one day.