The District’s online health-insurance exchange is grappling with “hundreds” of problematic applications from shoppers unable to enroll in health plans because of system error messages, an exchange spokesman said Friday.

Exchange officials are in the process of identifying the account holders and contacting them, said Richard Sorian, a spokesman for DC Health Link. Most of the problems appear to stem from duplicate accounts that shoppers may have created inadvertently.

The exchange, DC Health Link, is where thousands of congressional staffers and members are shopping for coverage by their Monday open-enrollment deadline.

Exchange officials have addressed several technological issues since the Oct. 1 launch. But new ones have cropped up as people have used the online system, and others appear to be persisting.

Legal immigrants who don’t have credit cards, for example, are having trouble getting their identities verified, preventing them from enrolling online. Instead, they have to use paper applications, according to Selamawit Teka, one of seven “assisters” at Mary’s Center, a community health center in Petworth. Online enrollment has been working well, except for the credit card issue for legal immigrants, she said.

An earlier issue involved error messages that often occurred when shoppers were choosing a health plan. Instead of receiving a confirmation, they received an “Error 500” message. A fix was put in place the weekend before Thanksgiving, Sorian said.

Other shoppers are receiving error messages because they have created duplicate accounts. That may have happened when frustrated shoppers weren’t receiving confirmations.

“We think it’s happening less, but likely still happening,” Sorian said.

Others, such as Nicholas Lefevre, have been unable to have their issues resolved even with assistance from the exchange.

Lefevre, 62, figures he has tried to enroll at least 100 times since Web site’s launch. He has coverage through a preexisting condition insurance plan that will end Dec. 31. To avoid an insurance lapse, he needs to sign up by Dec. 15.

For the first two weeks, the system had problems verifying his identity. For three weeks after, it crashed whenever he entered his income information. (He has more than one source of income — a Social Security survivor benefit and some dividend and interest income). Call center staff members told him the problem was a “known bug.” He hasn’t been able to access his account since Nov. 6.

Lefevre has been contacting the exchange by e-mail or via the call center daily. After signing in, he receives the same “Error 500” message.

On Friday afternoon, he reached someone who tracked down his application and saw that it was “pending.” But Lefevre is still unable to log in to his account to select and buy a plan. He said the call center staff member acknowledged the error and said exchange officials “are fixing it,” an answer Lefevre has received repeatedly.

Interest in the District’s exchange has surged. Call volume has increased from about 200 a day a month ago to more than 1,500 a day, Sorian said. The average wait time is about 40 minutes. To shorten wait times, a new recording on the call center line informs people who simply want confirmation of enrollment in a plan to e-mail their name, date of birth and the last four digits of their Social Security number to info@dchealthlink.