Shopify experienced an outage on Cyber Monday that interrupted transactions for some merchants on its e-commerce platform during one of the busiest shopping days of the year.

Shopify shares fell 6% on the news.

The web hosting company said on X it was aware of an issue impacting selected stores and was working to resolve it.

A spokeswoman referred questions to the company's status page, which said that merchants might experience difficulties logging into the point-of-sale system and other problems that the company was investigating.

Shopify provides tools such as payment processing and inventory management for merchants to sell products online. It started as a way for small businesses to have an e-commerce storefront but has also attracted larger retailers.

Adobe expects consumers to spend $14.2 billion online Monday, a 6.3% increase over last year.

About 4,000 users reported problems with Shopify's website at 11 a.m. The number fell to a few hundred by early afternoon, according to Downdetector, which monitors online services.

"We were completely in trouble, especially on a day like today when there is a lot of traffic on our" sites, said Myriam Belzile-Maguire, co-founder of family business Maguire Shoes based in Montreal.

Shopify's services went down about 9 a.m. and were restored around 2:30 p.m. Eastern time, Belzile-Maguire said. During that time, customers were able to submit orders, but the company couldn't monitor sales, track inventory or answer customer-service questions about shipments.

E-commerce is increasingly crucial for retailers, especially on days like Cyber Monday.

Online sales accounted for 16.1% of total retail sales in 2024, up from 15.3% in 2023, according to the U.S. Commerce Department. The penetration is far larger for categories that rank high on holiday-gift lists such as consumer electronics and toys.

Foot traffic to physical stores fell 2.1% on Black Friday compared with the same day a year ago, according to Sensormatic Solutions, which tracks shopper behavior. Meanwhile, people spent $11.8 billion online the day after Thanksgiving, a 9.1% increase over the same day in 2024, according to Adobe.

As people become more reliant on the internet, any glitches can cause major disruptions, as was the case earlier this year when technical problems at Amazon disrupted web services for millions of Americans.