Representatives from CGI Federal and Quality Software Systems Inc. (QSSI) at a hearing on implementation of the Affordable Care Act before the House Energy and Commerce Committee on Thursday. Alex Wong/Getty Images

Nevertheless, the contractors who built the buggy Web portal had to answer to the House Energy and Commerce Committee on Thursday during a hearing where the two companies, CGI Federal and Quality Software Systems Inc. (QSSI), faced tough questions about the problems Americans have faced in trying to sign up for health care.

According to the The Washington Post , administration officials said the extension is not a result of technical problems with the site, HealthCare.gov.

Previously, Americans would have needed to sign up by Feb. 15 to avoid penalties, according to The New York Times . Essentially, the administration is extending the February deadline by six weeks so it coincides with the end of the open-enrollment period for health insurance.

House lawmakers grilled the contractors who developed the glitch-plagued Affordable Care Act (ACA) website during a hearing Thursday, a day after the Obama administration said that people who obtain health insurance by March 31 would not face tax penalties for being uninsured.

"We expressed all of those concerns and risks," he said in testimony.

But Slavitt also said his company had warned the Obama administration about potential complications.

"It appears that one of the reasons for the high concurrent volume at the registration system was a late decision requiring consumers to register for an account before they could browse for insurance products. This may have driven higher simultaneous usage of the registration system that wouldn't have occurred if consumers could 'window shop' anonymously," he said.

"After the launch, HealthCare.gov was inundated by many more consumers than anticipated. Many of the critical components developed by these multiple vendors were overwhelmed," Slavitt said in the prepared remarks.

Andy Slavitt, an executive of QSSI's parent company, Optum, said the company had to create a registration system on short notice, and that could have contributed to overloading the system, which was built with other contractors, or "vendors."

In prepared testimony, executives from the two contractors pointed fingers at each other and the federal government.

CGI Federal was the lead developer of the federal site, and QSSI designed a hub that verifies applicants' personal information and income details. The administration says QSSI's part of the site is working as designed.

Lawmakers are trying to determine why the online portal for uninsured Americans in 36 states has malfunctioned since its Oct. 1 start, the beginning of a six-month enrollment period that is expected to draw at least 7 million people to sign up for federally subsidized private insurance for 2014.

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CGI vice president Cheryl Campbell said in her prepared testimony that the administration was the "quarterback" of the entire effort.

Her testimony seemed to place some of the blame on QSSI for its registration system, which created a "bottleneck" that stopped people from registering. With those problems mostly resolved, Campbell said, it is up to CGI to make sure that the exchange site is up and running, but she said some of the issues the site had already seen couldn't have been helped.

"We acknowledge that issues arising in the Federal Exchange have made the process for selecting and enrolling in qualified insurance plans difficult to navigate for too many individuals," she said.

"Unfortunately, in systems this complex with so many concurrent users, it is not unusual to discover problems that need to be addressed once the software goes into a live production environment."

But Campbell also said the online exchanges, while buggy, had some successes and would ultimately be fixed.

"The system is working. People are enrolling. But people will be able to enroll at a faster pace," she said.

CGI Federal is a subsidiary of a multibillion-dollar Canadian firm, CGI, and has created other federal websites, including the portal for Medicare. It has also been involved extensively in Housing and Urban Development contracts.

The company won a $93 million bid for the HealthCare.gov project in 2011. It has also recently ramped up its lobbying efforts in Washington, the Post reported.

Meanwhile, Democrats are worrying aloud about persistent problems with the rollout. Rep. Richard Nolan of Minnesota emerged from a Wednesday morning meeting with administration health care officials on Capitol Hill and told The Associated Press that the computer fiasco has "damaged the brand" of the health care law.

"The president needs to man up, find out who was responsible and fire them," Nolan said. He did not name anyone.

Likewise, in the Senate, Florida Democrat Bill Nelson said somebody should be held responsible for the glitches.

"That's the problem in government today," Nelson told ABC's Miami affiliate. "People are not held to account."

Obama says he's as frustrated as anyone and has promised a "tech surge" to fix the balky website. White House spokesman Jay Carney also said the administration will be more open about the problems.

After more than 20 days without briefing the media, the Department of Health and Human Services will start regular sessions on Thursday, he said.

On the defensive, the Obama administration acknowledged Wednesday that the problem-plagued website didn't get enough testing before going live. It said technicians were deep into the job of fixing major computer snags but provided no timetable.

Al Jazeera and The Associated Press