(CNN MONEY) -- A malfunction in key technology behind the Obamacare website left users unable to apply for health coverage late Sunday.
Joanne Peters, a spokeswoman for the Department of Health and Human Services, said a vendor networking issue at Verizon subsidiary Terremark was to blame. Peters said the vendor had "experienced a failure in a networking component," and the attempted fix crashed the system.
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Peters said that HHS chief Kathleen Sebelius had discussed the problem with Verizon CEO Lowell McAdam.
Verizon spokesman Jeff Nelson said his company was working on the issue and it would be "fixed as quickly as possible."
The outage was the latest issue to hit the troubled HealthCare.gov. Since a disappointing debut on Oct. 1, some users have been unable to create accounts or sign up for coverage.
This malfunction impacted the "Data Services Hub," which connects the website to IRS and other databases used to determine eligibility. On Saturday, HHS Secretary Kathleen Sebelius touted the "hub" as one of the Obamacare technologies that was working.
The malfunction not only impacted the troubled federal website, but also hit some
state-based exchanges. Peters said the problem was "likely impacting several other sites," and Kathleen Tallarita of the Connecticut insurance marketplace said some customers there could not sign up. Fourteen states and the District of Columbia elected to set up their own exchanges, which have been largely error-free.
President Barack Obama said in a speech last week teams were "working out the kinks in the system." He appointed former White House budget official Jeffrey Zients to oversee the repairs. Zients said the site would be working for "vast majority" of users next month.