The company's stock closed at $1,822.49, but slid about 1.5 percent in extended trading in NY.
The technical issues weren't limited to shopping.
The issues appeared to affect other Amazon products and services.
Prime Day is a study in retail's woes in microcosm: Amazon lowers prices of a number goods that consumers can expect to get on their doorsteps within a couple days-a value, speed, and convenience proposition that's hard for others to match.
The 36-hour event was projected to break records again this year, with industry analysts estimating the company could make at least $3.4bn (£2.6bn) in sales. They recovered in the second and third hours, according to Feedvisor, which is monitoring the event.
Amazon itself hasn't disclosed specifics, but Feedvisor's estimates are based on results from its clients. "Unless this is way beyond their wildest expectations, it's just odd".
Here's the biggest bummer of Prime Day for Nintendo fans: Very few Switch games or 3DS games have gone on sale.
Amazon's Prime Day outages trip up shoppers
Amazon Prime Day 2018 is finally here once more, and with it are a swath of excellent gaming deals that you'll definitely want to jump on.
"It wasn't all a walk in the (dog) park, we had a ruff start", Amazon said in a statement early Tuesday. You can get an Echo Dot for $30 today, which is 40% off the regular price of $50. "Someone has made a change and it's not compatible".
This week's strikes have also inspired widespread calls for shopper boycotts on social media platforms such as Twitter.
Site highlights each day to your inbox. Amazon recommends that shoppers download the free Amazon app.
Amazon are also offering its Prime members four months of Prime Music for just 99p!
The action adds to Amazon's Prime Day difficulties.
To take part in Prime Day, you will need an Amazon Prime account. Amazon said it was trying to fix the problem.