Problems plagued Amazon Tuesday on one of its biggest days of year. Some users reported having issues checking out on the retailer's second-ever Prime Day, an event that give members of Amazon's Prime service access to special deals. 

"Some customers are reporting difficulty with checkout. We're working to resolve this issue quickly," Amazon tweeted Tuesday morning. 

Users on Twitter posted that when they went to check out, they received a "cart failed" error message. Potential shoppers would apparently click on items, only to be told the action had failed and it was retrying. International Business Times reached out to Amazon for comment and will update this story with any further statement. 

The company was likely hoping for a smooth event this year after the inaugural Prime Day last year was plagued with issues like top items selling out extremely quickly. The 2015 event was the biggest international sales day ever for the company, according to Amazon.

The retailer said in a press release it would feature Tuesday "more than 100,000 deals worldwide exclusively for Prime members, making it the biggest Amazon event ever." Prime Day is open only to members of the subscription service, but Amazon allows users to to sign up for a free 30-day trial to take advantage of the deals.

Time Magazine noted in the lead-up to Prime Day that Amazon could face "brutal" backlash if the event again frustrated users. Last year the hashtag #PrimeDayFail took off with social media users complaining about the good deals selling out, lackluster savings and featured items that nobody particularly wanted.

Amazon was seemingly aware of some of these issues. "Following last year’s record sales, we have dramatically increased the inventory behind many deals. In fact, in the U.S. we have nearly double the TV units compared to Black Friday and Cyber Monday combined," said Greg Greeley, vice president of Amazon Prime, in a statement ahead of Prime Day 2016. "Even with this massive selection we know many of the Prime Day offers will sell out, so members should download the Amazon shopping app to receive notifications on their favorite deals."