Some of the biggest websites across the world are down, including the UK government and Amazon.
Lots of sites across the world have crashed such as PayPal, Spotify, Reddit and media organisations such as the BBC and The Guardian.
CNN and France’s Le Monde also started showing error messages that appeared on the websites at around 10:00 GMT. Al Jazeera Media Network was also affected.
The issues appear to be because of a problem with Fastly which is a cloud computing company that provides services to many websites.
Hundreds of people took to social media network Twitter to speak about the issues, with people tweeting links to sites that were down.
As yet there has been no statement from Fastly about the outage.
We'll be bringing you all the latest news on this incident as we get it in our live blog below.
Fastly issue identified
The outage appears to have been sparked by an issue with a content delivery network (CDN), a system used to host websites and their content on the internet and serve it to users.
Fastly, one of the world's major CDNs, has reported a major outage across its global network, which is believed to have caused the outage.
The company offers services such as speeding up loading times for websites, protect them from denial-of-service cyberattacks and helping them deal with bursts of traffic in order to stay online and stable.
The US-firm has confirmed it is "currently investigating potential impact to performance with our CDN services".
Issue linked to Fastly
Several websites affected by a major outage are reporting that the issue is linked to Fastly, a cloud computing services provider.
Alex Hern, the Guardian's technology editor, tweeted that Fastly "has been identified as the cause of the problem".
He tweeted: "The outage, which began shortly before 11am UK time, saw visitors to a vast array of sites receive error messages including 'Error 503 Service Unavailable' and a terse 'connection failure'."
The Quartz site has also attributed the issue to Fastly via Twitter.
Media websites down
Websites for several leading media companies – including the Guardian, Financial Times, Independent, and the New York Times are also down.
The Guardian tweeted: "The Guardian's website and app are currently being affected by a wider internet outage and will be back as soon as possible."
Other websites affected included the online discussion platform Reddit, the Evening Standard and French newspaper Le Monde.
UK government website down
The UK Government's website is among a number giving error messages on Tuesday morning in what appeared to be a worldwide internet issue.
Anyone attempting to access the gov.uk site – was given the "Error 503 Service Unavailable".