• Some customers reported a glitch on Monday that prevented them from loading items into their Amazon carts.
  • It's the second straight year of technical glitches for Prime Day, following last year's site outage. 
  • EBay pounced on the glitch, tweeting to shoppers about its competing Crash Sale. 

Amazon Prime Day arrived with a glitch for some customers who found they couldn't load items into their online shopping carts. It's the second year in a row that Prime Day has suffered technical problems, following last year's site outage. 

"Amazon would love to buy things for #primeday but keep getting a FAILED TO ADD TO CART error," one customer tweeted on Monday. Others complained about similar issues, expressing frustration at their inability to make purchases. Amazon didn't immediately return a request for comment. 

At least one competitor jumped on Amazon's tech problems, with eBay flagging the glitch and encouraging shoppers to check out its competing "Crash Day" sale. EBay and other retailers are hitching their own sales to Amazon's Prime Day by banking that many consumers without Amazon's $119 annual Prime membership may want to check out deals on their sites.

The stumble comes amid speculation about whether Prime Day might suffer a repeat outage. Gamblers could even place a bet ahead of Prime Day on whether the site would go down again this year, although the money was against any major crash. A $100 bet that Amazon.com would suffer an outage was slated to return $325. That indicates the odds are against an outage because an event that's viewed as less probable will pay higher returns.