X suffered a prolonged outage at 12am ET.
The cause of the issue with the social media platform, formerly known as Twitter, has not been disclosed.
Since Elon Musk's $44 billion acquisition late last year, the service has experienced multiple major outages.
Musk laid off a large proportion of the company, closed data centers, and curtailed cloud spend (in some cases, he refused to pay cloud providers).
This latest outage is believed to be the platform's largest since the acquisition, but X has outlived some critics' claims - with former employees saying that it would be brought fully offline due to the cuts.
X is now believed to be worth around $19 billion.
