Facebook has said a 'configuration change' is believed to be responsible for causing problems for thousands of users in the United States and Europe on Friday night, with some unable to access the site and others reporting that porn had flooded their video feeds. Downdetector.com which measures website problems saw the problems start to occur around 10pm EST. At least 4,800 users in the U.S. reported on Downdetector that they were unable to log in. It seemed the problem was mostly resolved on Saturday morning, although some users still reported problems. 'We're looking into reports that some people are currently having to login again to access their Facebook accounts,' the company said in a statement. 'We believe this was due to a configuration change and we're working to get things back to normal as quickly as possible.'