"It's kind of an architectural and software issue," Wu said. "You are not accounting for how people want to use the system."
With personal accounts, the computer system has to work harder, storing information about everyone who accesses the website, he said. It also has to repeatedly confirm the identity of the person, which also can bog down the system, Wu said. He noted that all the functions on the website that don't require an account have run smoothly.
"It has to match your account every step you make," Wu said. "This causes extra overhead."
Pearce has said the log-on information is meant to serve as a security function to protect people's identity.
The way to fix the problem, Wu said, is to add additional server capacity to handle the traffic volume, or improve the software, which is a much more complicated and time-intensive task.
Community groups tapped to help Marylanders enroll in insurance plans have needed to adjust to the unexpected problems with the exchange.
"It's been very, very challenging because the Web portal has not been at the highest level it should or could be," said Kathy Westcoat, executive director of Health Care Access Maryland, a Baltimore nonprofit that is helping to enroll people.
Westcoat's group has stopped using the website because it was taking several hours to process people. The organization is using paper applications instead. That means applicants won't know the same day if they qualify for insurance. It is also harder to compare plans.
Westcoat has said she has noticed small improvements each day.
Columbia-based Healthy Howard Inc. said it also continues to use paper applications because of reports of continued technical issues.
Amanda White, a senior analyst with software provider Deltek, also said software issues seem to be the problem, but the backlog shows that people are interested in finding out about insurance plans offered under reform.
"This isn't necessarily a bad thing," she said. "They are working diligently to address all the problems as they come up. It's not like these problems aren't going to be fixed."
Pearce also said the interest bodes well for the law's success. "We appreciate the sustained, strong interest in Maryland Health Connection and in accessing quality and affordable health care," she said.
Westcoat said while people are frustrated, many still want to shop for a health plan. They have until March to enroll, but must sign up by mid-December for coverage starting Jan. 1.
"We are just trying to send the message that there is time," Westcoat said.
Howard Kahn of Pikesville has tried since Tuesday to establish an account for his son. He was able to fill out a form Thursday, but the screen froze. He telephoned a call center but said he'd rather create the account himself, so he can take his time. He still could not access the site Friday afternoon but said he will wait for the state to work out the kinks.
"I am frustrated that it hasn't worked all this time," he said. "I believe it is extremely important that everybody who wants to take advantage of this momentous change will be able to do so. It is unfortunate there are technical difficulties."