Many reported the platform had crashed as soon as the two-day sale day began on 16 July, showing them only an error message that read: "sorry, something went wrong on our end", >reports the BBC.
The issues are centred on the US but occurring on other continents too.
DownDetector.com, which tracks outages, most of the outages are centred on the US. However, it was also reported in Europe, Africa, South America, Russia, Asia and Australasia.
Others also reported experiencing problems with Amazon's video streaming services and its virtual assistant Alexa.
According to reports, users have experienced errors on both the desktop site and the mobile app, the BBC reported.
Some saw an error page featuring the "dogs of Amazon" and were unable to enter the site, while others could not enter specific product pages.
Many were unable to complete purchases at checkout, while others reported that the "deals" page and "Shop all deals" button had disappeared from the site.
Amazon launched Prime Day in 2015 and by 2017 it was its second biggest shopping day.
The 36-hour event was projected to break records again this year, with industry analysts estimating the company could make at least $3.4 billion in sales.