There were more than 21,000 incidents of people reporting issues with the platform in the U.S. and more than 10,800 incidents in the UK. Downdetector.com tracks outages by collating status reports from a number of sources. The actual number of affected users may vary. Remove Ad X did not immediately respond to a Reuters request for comment. The social media platform went down briefly for thousands of users in the US and the UK on Monday. The company has since resumed service. The number of people affected by the outage has not been released. It is not clear when the service will return to normal. The site has not yet responded to a request for a comment from Reuters. The website is based on user-submitted reports and the number of users affected may vary depending on the location and severity of the issue. The platform is owned by Facebook, which also has its own social media site, Ad X, which has not responded to requests for comment on the outage.