Internet infrastructure company Cloudflare was hit by an outage on Tuesday, knocking several major websites offline for global users.

OpenAI’s ChatGPT and Elon Musk’s social media platform X appear to have been affected by the Cloudflare issues, according to Downdetector, which itself could not be accessed for some users.

OpenAI’s status page also indicated its ChatGPT and Sora short-form video app were having issues due to “an issue with one of our third-party service providers.”

A Cloudflare spokesperson said the company observed a “spike in unusual traffic” to one of its services around 6:20 a.m. ET, causing some traffic passing through its network to experience errors.

“We do not yet know the cause of the spike in unusual traffic,” the spokesperson added. “We are all hands on deck to make sure all traffic is served without errors.”

The company said it was “continuing to investigate” the issue in updates posted to its system status page.

Cloudflare’s software is used by many businesses worldwide, helping to manage and secure traffic for a 20% of the web. Among the services it provides are that it guards against distributed denial of service attacks, which are when malicious actors attempt to overload a website’s system with so many traffic requests that it can’t function.

Shares of Cloudflare slid more than 5% in premarket trading.

The issue comes less than a month after Amazon Web Services suffered a daylong outage that took down numerous online services, followed by a global outage of Microsoft‘s Azure cloud and 365 services.

This story is developing. Please check back for updates.