The website at the center of the U.S. healthcare reform law was back up Monday after a data center outage prevented Americans from enrolling in subsidized health insurance, the latest technical problem to plague the online insurance exchanges. The outage, which started before dawn on Sunday, affected not only the federal government's online exchange, HealthCare.gov, but also those run by 14 states and the District of Columbia, the Department of Health and Human Services said. HHS spokeswoman Joanne Peters said on Monday the website itself as well as a crucial piece of Obamacare - a data services hub that determines if people are eligible to buy health insurance on the exchange - were both back online as of 7 a.m. EDT after being restored late Sunday and tested overnight.