Internet users faced problems accessing many websites for about an hour because of a problem with Cloudflare.
The company provides internet security and other services meant to help online businesses operate smoothly.
Many members of the public had reported seeing "502 errors" displayed in their browsers when they tried to visit its clients.
The service has more than 16 million customers ranging from the chat service Discord to the dating site OKCupid.
Cloudflare said the problem had now been resolved although some of its analytics tools were still facing disruption.
Among the casualties was Downdetector, a popular site used to monitor disruption.
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CoinDesk - a news site specialising in cryptocurrencies - was also one of those affected. It said that it had received bad data from its providers as a consequence, which resulted in it misreporting prices.
"Calm down everyone, Bitcoin is not $26," it tweeted before adding that it had now resolved the issue.
A 502 error code signifies that an internet server has received a invalid response from another server it is trying to contact.
There has been speculation that San Francisco-based Cloudflare had suffered a distributed denial of service (DDoS) attack - in which it had been flooded with traffic.
But it has denied this was the case and has blamed the incident instead on a "bad software" update that had been "rolled back".
"This was not an attack (as some have speculated) and we are incredibly sorry that this incident occurred," blogged John Graham-Cumming, the firm's chief technology officer.
"Internal teams are meeting as I write performing a full post-mortem to understand how this occurred and how we prevent this from ever occurring again."
The Register reported that the firm also experienced issues last week, although that time it appears that the telecoms network Verizon was at fault.