Millions of Americans have shown an interest in checking out the new options, but it appears that few have been able to get through the online application process.
Marilyn Tavernner heads Medicare and Medicaid Services, the agency in charge of the troubled website.
On Tuesday, she issued an apology to those unable to sign up, while testifying before a House committee.
"We know how desperately you need affordable coverage," she said. "I want to ensure you that healthcare.gov can and will be
fixed, and we are working around the clock to deliver the shopping experience that you deserve," Tavernner said.
On Wednesday, a congressional committee will grill Tavernner's boss, the Health and Human Services chief.