Amazon’s checkout function encountered technical issues on Friday, keeping customers from completing purchases. The e-commerce site displayed error messages with photos of dogs during the outage as people posted about it on social media.

The company’s Amazon Web Services division was not reporting any technical issues while the checkout feature wasn’t working. AWS downtime can lead to problems across the internet because so many companies rely on the market-leading public cloud.

In the run-up to the long weekend in the U.S., Amazon has started promoting discounts on products as part of a Labor Day sale. But people weren’t able to purchase discounted products because of the glitch, as some people pointed out on the X social network.

The Amazon Help account on X replied with a recommendation to contact the company.

Amazon has warned investors that technical incidents can lead to lower sales and a worse perception of the company’s products and services. Sales are healthy at almost $148 billion in the second quarter.

The outage is a minor setback for the company, which has been experiencing a strong sales period. Amazon’s Prime Day sales rose about 13% in the first six hours of the event compared with the same period last year, according to Momentum Commerce, which manages 50 brands in a variety of product categories.

Amazon relies on its own data center infrastructure to run its website, which may have contributed to the technical issues. The company did not immediately respond to a request for comment.