San Francisco, California - Hundreds of websites and platforms were knocked offline after an outage at web infrastructure service Cloudflare.

Internet users and web monitoring service Down Detector reported that a number of sites, including messaging platform Discord, Shopify and others, were having issues on Tuesday morning.

Visitors to that site and many others got the dreaded "500 Internal Server Error" message.

Cloudflare said it has now resolved the issue.

The San Francisco-based company is a content delivery service and its technology helps to power many of the major websites used by internet users every day.

In a series of posts to the firm’s official Twitter account which began just before 3 AM EDT on Tuesday, Cloudflare confirmed it was aware of the "current service issues" and said its team was "working to resolve as quickly as possible."

Since then, the company confirmed it had identified the issue and a "fix has been implemented" and that it was "monitoring the results," before finally confirming that the issue had been resolved.

Down Detector also showed many websites starting to come back online in the wake of the outage.