Early warning signs
Some of the criticism surrounding the website's launch has to do with what Obama and other officials knew -- and when they knew it.
CNN has learned the administration received stark warnings a month before the launch that the health care site was not ready to go live, according to a confidential report. The caution, from the main contractor CGI Federal, warned of risks and issues for HealthCare.gov, even as company executives were testifying publicly the project was on track.
Sebelius told the House committee the outside contractors who built the website never recommended delaying this month's launch. But she conceded that "we did not adequately do end-to-end testing."
The contracts with the private companies working on the website -- which amount to $174 million so far, with more bills due well into 2014 -- do not have "built-in penalties" allowing her department to charge them for disappointing or faulty work, Sebelius said. But Sebelius said the agency will not pay for incomplete work.
Republican Rep. Mike Rogers of Michigan, who chairs the House Intelligence Committee, accused Sebelius of putting the private information of Americans at risk by failing to properly test security measures on the website.
"This is a completely unacceptable level of security," he said. "You know it's not secure."
Sebelius responded that testing occurs regularly, and she told Rogers she would get back to him on whether any end-to-end security test of the entire system has ever occurred. Rogers said he knows there have been no such comprehensive security tests.
An internal government memo obtained by CNN on Wednesday that was written days before the website launched warned of a "high" security risk because of a lack of testing.
"Due to system readiness issues, the (security control assessment) was only partly completed," said the Centers for Medicare and Medicaid Services memo. "This constitutes a risk that must be accepted and mitigated to support the Marketplace Day 1 operations."
Sebelius told CNN last week that Obama didn't know of the problems with the site -- even though insurance companies had complained and the site crashed during a pre-launch test run -- until after it went live.
A senior administration official said Obama now gets a "nightly readout" with the latest ACA statistics and an update of the website's status.