The Obamacare website registering consumers in new insurance exchanges suffered another major glitch, losing connectivity on Sunday.

The crash came as officials rolled out new changes to the beleaguered website which has been plagued with a host of technical problems since its Oct. 1 launch.

Health and Human Services blamed the downed website on an issue with an outside contractor, Terremark, which operates a data center hosting

“Today, Terremark had a network failure that is impacting a number of their clients including,” said HHS spokesperson Joanne Peters. “Secretary Sebelius spoke with the CEO of Verizon this afternoon to discuss the situation and they committed to fixing the problem as soon as possible.”

Telecommunications giant Verizon has been tapped by the administration to help repair the site.

The glitch-filled rollout of the health insurance exchanges has become an embarrassment for the White House, with critics of Obamacare seizing on the missteps and arguing that the entire law is unworkable.

President Obama has said the administration is frustrated with the website problems, but has vowed to repair them quickly. Obama and his surrogates, though, have defended the healthcare law, saying that despite the website, the rest of Obamacare is working well and already delivering benefits to millions of Americans.

White House press secretary Jay Carney on Monday said that Verizon Terremark’s team had “successfully resolved” the problems overnight and that by 7 a.m. the data services hub for the website was “fully operational.”

“We have acknowledged that has not performed adequately and the president is not happy about that, Secretary Sebelius is not happy about that,” said Carney. But he added that “this isn’t about a website” and touted Obamacare’s benefits.

HHS is encouraging consumers to enroll via phone or mail as the website is repaired. Former Office of Management and Budget Director Jeffrey Zients has been tapped to oversee the effort. Last week Zients vowed that the website would be running “smoothly” before the end of November.

Sebelius and Centers for Medicare & Medicaid Services Administrator Marilyn Tavenner are both slated to testify before Congress this week.

This story was published at 6:29 a.m. and has been updated.