Connecticut’s health insurance exchange advised people who want to buy health care coverage before midnight to call the agency’s call center at 1-855-805-4325.

Access Health CT CEO Kevin Counihan said in a statement that some people are having trouble getting through to the exchange because of problems with the federal data hub used to verify applicant information and a surge in demand.

“Because we do not want people who are making a good faith effort to be penalized, we are asking people to call 1-855-805-4325. If necessary, you will be prompted to leave your name, address and a phone number in a secure voicemail where an Access Health CT employee will get back to you over the next few days to complete your enrollment,” the statement said.

“All messages left before midnight, March 31st, will be considered as meeting the enrollment deadline.”

Midnight is the deadline for signing up for private insurance through the exchange, and Counihan said there has been a substantial increase in the number of people trying to sign up.

Gov. Dannel P. Malloy and Lt. Gov. Nancy Wyman joined Counihan as a press conference to pronounce the rollout of Obamacare in Connecticut to be a success, with nearly 200,000 clients signed up as of 5 p.m.

As they spoke, a computer screen behind them showed as many as 1,335 people were on the Access Health CT web site.