"HealthCare.gov is making accurate determinations for nearly all users," said Emma Sandoe with the U.S. Centers for Medicare and Medicaid Services.
"We are working to implement additional fixes soon for bugs that are impacting a limited number of people," including those with complicated family or tax situations, said Sandoe. The exchange has beefed up staffing at its call centers and is reaching out to consumers who have run into trouble, advising them to reset their applications or file an appeal, she said.
Navigators, who are trained to help consumers enroll, encourage frustrated shoppers to contact them because they can troubleshoot applications directly with the exchange's "resolution center."
Families and individuals who earn incomes between 100 and 200 percent of the federal poverty level seem most vulnerable but not everyone within this range is getting hung up, they say.
"We haven't identified the trigger points. We have people below that range who sail through and others who don't," said Jason Stevenson, a spokesman at the Utah Health Policy Project, which oversees a network of navigators through Take Care Utah.
"It's unfortunate that this is happening right when people are starting to tune in and the website is working. The fear is that it will sour people and cause them to turn away."
And persistence can pay off.
"I just kept trying," said Mary Ellen Riley, of Sandy, who secured a subsidized plan this week after four tries and several fruitless calls to state and federal officials.
The 61-year-old lives alone and has one source of income that puts her well above income limits for Medicaid, Utah's threshold and a more generous limit proposed by the Affordable Care Act.
But the first time she entered her information on the exchange application at HealthCare.gov the subsidy calculator deemed her eligible for Medicaid. This meant she couldn't apply for a subsidy, though she could buy a full-priced plan.
Riley called Utah's Medicaid program, which confirmed what she already knew that she didn't qualify. She phoned the exchange hotline several times and was given various erroneous explanations but no help.
"They said, 'There's nothing we can do. There's nothing you can do,' " said Riley. "They need someone there with a brain or some power."
On Monday an operator offered to wipe her old applications from the system and push through a third, but it showed she qualified for another low-income health plan, this one for kids the Children's Health Insurance Program.
"They told me I have to appeal and promised me it would be resolved," she said.
And it was, though it's unclear how. Riley tried applying for a fourth time on Thursday and it worked.
She purchased a SelectHealth plan similar to the one she has now, only it has a smaller deductible and will cost her less.
After the subsidy was awarded, Riley will pay $183 a month, down from her previous monthly bill of $306.
"Now I just have to wait until SelectHealth gets a record of my application so I can pay my bill," she said. "I have to pay it by Monday."
Consumers have until Monday to purchase health coverage that takes effect in January. The online insurance exchange HealthCare.gov will stay open for enrollment, however, through March 31.
Need help enrolling?
There are several options for those who need help shopping the Affordable Care Act's online health exchange:
Online chat at healthcare.gov
Toll-free call center at 1-800-318-2596
Go to www.takecareutah.org or call 211 to find the nearest trained navigator
Find a certified insurance broker near you at bit.ly/brokerfind