Trading was halted across much of the Chicago Mercantile Exchange early Friday with the group blaming a "cooling issue" at a partner's data center.

An outage at the world's biggest exchange operator CME Group on Friday halted trading on its popular currency platform and in futures spanning foreign exchange, commodities, Treasuries and stocks.

The Aurora, Illinois, complex has served as the primary hub of digital operations for the world’s largest futures exchange operator CME Group Inc. for nearly two decades. Traders want to be close to the data center to reduce latency,

CME Group (CME) said in a social media post that its markets are now open and trading after a cooling issue at CyrusOne data centers led to a halt in trading across its markets.

Bourses operated by CME include the Chicago Board of Trade, the New York Mercantile Exchange and the Commodity Exchange. CME also has a stake in other exchanges, including the Gulf Mercantile Exchange, which said in a notice to the market that it had also seen trade halted due to the cooling issue.

US stock futures were muted heading into the end of a holiday-shortened week, before the Chicago Mercantile Exchange halted trading on Friday due to a data center glitch. The ongoing CME outage has disrupted live trading in futures and options across several markets,