Many Shopify merchants were unable to log into their Shopify web stores or use Shopify’s point-of-sale system in their physical stores as the e-commerce giant battled a partial service outage on Cyber Monday, one of the biggest shopping days of the year.

After initial reports of finicky performance issues in some of the services Shopify offers its merchants, by mid-afternoon in the Eastern time zone Monday the company acknowledged a “partial outage” of its merchant administrative and in-store checkout services. By Monday evening, Shopify said it had “found and fixed” a login authentication flow issue, according to its website, and was monitoring recovery. The company, which declined a request for comment, also said its help centre was experiencing longer than normal wait times.

Shopify shares closed down 6.3 per cent on the Toronto Stock Exchange Monday, and 5.9 per cent on the Nasdaq.

Shopify started investigating login issues around 10 a.m. ET, according to its website. The statement it published said merchants may also experience trouble getting into their point-of-sale devices and mobile services, as well as contacting support. The company asked those who are able to access their stores to stay logged in.

Sam Wright, managing director of Blink SEO, a U.K.-based marketing agency that works with Shopify stores, told The Logic he first spotted a problem at one of his client’s stores around 9 a.m. ET and then confirmed it was a wider issue across his client base. Those that can’t log into their accounts, he said, are unable to track their Cyber Monday sales performance, send marketing emails or offer support to their customers.

Krishna Krishna, a Vancouver-based entrepreneur who uses Shopify to power several businesses he has founded, said he first noticed an issue at 8:45 a.m. ET. “Their entire system is down,” he said, noting it’s changed what his staff are able to do throughout the day. One of his clients has informed him their Shopify point-of-sale system is not working, he added. 

Krishna noted it is rare for Shopify to go down in such a manner.

Other merchants posted complaints about the outage, saying they’re unable to ship orders, see inventory figures or send marketing emails. 

Coming after Black Friday, Cyber Monday caps what has become one of the busiest retail sales periods in North America. On Friday, Shopify merchants sold US$6.2 billion worth of goods, according to Shopify president Harley Finkelstein, up 25 per cent from last year’s Black Friday sales. At one point, Shopify merchants in total were clocking US$5.1 million in sales per minute, according to Finkelstein. “The biggest weekend in commerce is off to an incredible start,” he said after announcing the figures.

Editor’s note: This story has been updated to include Shopify’s share information and progress in addressing the outage.