Bank, airline websites go dark briefly in international internet outage

A plethora of websites operated by financial institutions, governments and airlines including Hong Kong Exchanges & Clearing Ltd. and Australia’s central bank went down briefly Thursday in what appeared to be a widespread internet outage.

Website tracker Downdetector.com initially flagged hundreds of user complaints about outages affecting Southwest, Delta Air Lines Inc. and Automatic Data Processing Inc. Other websites pinpointed included those operated by Vanguard, E-Trade, Navy Federal Credit Union.

The widespread downtime recalled an hour-long global outage earlier this month, triggered by a software failure at content delivery platform Fastly Inc. The resultant cascading failures, which affected services from Amazon.com Inc. to Shopify Inc. and Stripe Inc., served as a stark reminder of how exposed the world’s biggest websites are to the impact of disruptions ranging from simple human error to coordinated cyberattack.

Many of the websites affected on Thursday recovered within the hour. Companies including Hong Kong’s exchange and Southwest said they were investigating the incident, without elaborating. “The pause in connectivity did not impact our operation,” Southwest said in an emailed response to questions.