A string of of high-profile websites, including X, ChatGPT and Spotify, went offline for users on Tuesday due to problems affecting internet infrastructure firm, Cloudflare.
Thousands of users reported issues with a host of different websites, including the film review site Letterboxd, which were impacted by technical issues at the network services business.
Multiplayer games such as League of Legends and the Scottish Parliament website were also impacted.
Users also reported issues with Shopify, Dropbox, Coinbase, and the Moody's credit ratings service. The Standard’s website was also affected.
Cloudflare said the "significant outage" occurred after a configuration file designed to handle threat traffic did not work as intended and "triggered a crash" in its software handling traffic for its wider services.
"We apologise to our customers and the Internet in general for letting you down today," it said in a statement.
"Given the importance of Cloudflare's services, any outage is unacceptable," the company added.
The DownDetector monitoring site, which was itself hit by the outage, showed a flurry of reported issues after 11am on Tuesday.
More than 10,000 DownDetector users reported issues related to Cloudflare.
A number of the websites affected came back online temporarily before suffering further problems.
Users saw a message on a number of the websites saying the issues were caused by an "internal server error on Cloudflare's network".
Cloudflare provides network and security services for many online businesses in order to help their websites and applications operate.
The company said in a server update that it was "experiencing an internal service degradation" and that some service may be intermittently affected.
It added: "We are seeing services recover, but customers may continue to observe higher-than-normal error rates as we continue remediation efforts."
Cloudflare said it had restored dashboard services but was still working to "remediate broad application services impact".
In an update at around 3.40pm UK time, it said its engineers were still mitigating some lingering issues after they posted a fix for the outage, but that they were continuing to monitor for any further problems.
It was understood the issues had largely been resolved by mid-afternoon with the majority of websites up and running.
Cloudflare, which runs services such as checking that visitors to websites are humans rather than bots, says around a fifth of all global websites use some of its services.
Cloudflare had scheduled maintenance for the SCL (Santiago) data centre for Tuesday.
Alan Woodward, professor of cybersecurity at the University of Surrey said: "The downside of being a gatekeeper and distribution network for such big brands is that if this vital system fails, no one can use your service be that website or app.
"It's still not clear exactly what went wrong but it looks like it was a technical malfunction within Cloudflare network.
"This in itself is surprising as such networks are designed to avoid single points of failure."
