Weeks after the Obama administration’s flagship health care website launched, users are still experiencing countless glitches, bugs and other problems, leading a key official in the administration to call the Healthcare.gov website’s rollout unacceptable at a congressional panel on Tuesday.

Marilyn Tavenner, administrator for the Centers for Medicare and Medicaid Services, appeared in front of the House Ways and Means Committee on Tuesday to apologize for the poor performance of the agency’s health care site. 

"The initial consumer experience of Healthcare.gov has not lived up to the expectations of the American people and is not acceptable," Tavenner told the committee.

“I want to apologize to you that the website is not working as well as it should,” she continued. “I want to assure you that HealthCare.gov can be fixed, and we are working around the clock to give you the experience that you deserve.”

In the four weeks since the Obama administration launched Healthcare.gov, the site has been riddled with errors, including long waiting times, glitches, and a complete outage between Sunday and Monday. Many users were unable to sign up for the site’s healthcare services, and those who managed to, often had difficulty logging in to the site later. Republican politicians in particular have attacked the site’s poor performance as an indicator of Obamacare’s overall quality.

In her testimony at the House Ways and Means Committee, Tavenner blamed many of the site’s problems on its contracted designers, stating that many who were hired to work on the website “did not meet expectations.” She also added that many of the site’s initial problems were caused when the "initial wave of interest stressed the account service, resulting in many consumers experiencing difficulty signing up, while those who were able to sign up sometimes had problems logging in."

Tavenner went on to claim that the Centers for Medicare and Medicaid Services have hired a new crop of talent to fix problems plaguing the site. These new hires are reportedly working around the clock to fix user-reported errors and improve the site’s overall usability. Tavenner also added that users are continuing to create accounts at a fast pace.

“We are pleased with these quick improvements, but we know there is still significant, additional work to be done," she said.

Still, despite Tavenner’s claims that Healthcare.gov can and will improve soon, "These problems can’t be fixed through a tech surge, and they’re not just a glitch in someone’s health care coverage,” House Ways and Means Chairman Dave Camp (R-Mich.) said as he opened the hearing.

Watch a video of Tavenner’s apology over Healthcare.gov below.