"We did believe that," senior White House strategy and communications adviser Dan Pfeiffer told the ABC's "This Week."
He made his comment after the program played a Sept. 26 CNN clip in which Pfeiffer touted the HealthCare.gov federal exchange plan enrollment website, which started for the public Oct. 1, as "a consumer experience unmatched by anything in the public, but also in the private sector."
"The president asked these questions -- those are the answers he was given," Pfeiffer told "This Week."
"These results do not match up to his expectations or the American people's expectations," Pfeiffer added. "It is inexcusable. There is no question about that."
Two private contractors testified before a House panel last week they told administration officials the site had troubles two weeks before it opened to the public but the officials swept aside their advice to meet the Oct. 1 deadline.
The federal site -- for residents of the 36 states that didn't create their own state healthcare exchanges -- has been marred by serious technological problems from its debut, making it difficult and impossible in some cases for individuals and small businesses to sign up for health insurance.
The Obama administration has promised the site will be fixed by the end of this month.
The site contained a message across the top of it early Monday alerting visitors it was down for a few hours.
"The Health Insurance Marketplace online application isn't available from approximately 1 a.m. to 5 a.m. EST daily while we make improvements," the message said. "Additional down times may be possible as we work to make things better. The rest of the site and the marketplace call center remain available during these hours."
Obama is facing severe criticism for the troubles, as well as allegations he knowingly oversold the Affordable Care Act to get the bill passed by Congress.
"Had the president been truthful and told the American people that millions would lose their insurance and millions more would see their premiums skyrocket ... there would have been such a hue and cry against it, it would not have passed," Mitt Romney, who lost to Obama in the presidential election last year, told NBC's "Meet the Press."
Hundreds of thousands of people have received letters saying their plans will be canceled or changed due to new minimum standards required under the law.
Former White House senior adviser David Axelrod told NBC, "Many of the people who have to transition are going to get better insurance for less money, but they just can't tell that right now because they can't get on the website."
Pfeiffer acknowledged "controversy and confusion" about Obama's original repeated claim in 2009 Americans could keep their current health insurance plans if they liked them.
He said Obama tried to clarify that in Boston last week, when he admitted for the first time that some people who have what Obama called "substandard" insurance plans may have to choose another one now that the Affordable Care Act has gone into effect.
But he said the vast majority of people can keep their health plans if they like them.
The Wall Street Journal reported Saturday discussions were going on behind the scenes in the White House and Obama advisers decided the assertion was fair, although there was second-guessing at times.
"I can't go back in time on this," Pfeiffer told "This Week." "Like I said, I don't recall this debate The Wall Street Journal talks about in any way, shape or form."
When asked again if this ever came up, Pfeiffer said, "Not that I remember."