NEW YORK — Problems have continued to plague the rollout of the health insurance exchanges under the Affordable Care Act.

Millions of people have been unable to enroll in health plans through the online exchanges, while others have found they lack tools for comparing policies and determining coverage and network providers.

That has been true for many state exchanges, even though their websites were working better than the federal exchange — which had not let many users even log on.

As of the middle of the month, just four exchanges — in Colorado, Kentucky, Nevada and Washington — had search tools for determining whether providers were included in particular plans.

California had to suspend its search tool after it was found to have inaccuracies and to freeze during use. Other states, including Rhode Island, Maryland and Oregon, were working to add search functions to their sites.

States with no search tools, including Hawaii, Vermont, Connecticut, Minnesota and New York, provide links to insurance company websites to get provider lists. However, those sites can be hard to navigate and may contain ­inaccuracies.

According to data that was tabulated by the Wall Street Journal, more than 38,000 people signed up for insurance through the 14 state-run exchanges through mid-October.Another 100,000-plus had ­completed applying and were close to being enrolled.

Maryland, which has about 600,000 uninsured residents, had enrolled 1,121 as of early October, according to USA ­Today. The state reported that more than one-third of those signing up were under 35. The Obama administration is hoping that young, healthy enrollees will offset the cost of insuring sicker people.

The federal government, which is operating an exchange for the 36 states without their own, will release enrollment data in November.

A Department of Health and Human Services (HHS) spokeswoman said the numbers showed “strong interest” in joining plans, the Wall Street Journal reported. And many people were weighing their options, she said, noting that there were more than five months to go until the end of open enrollment on March 31.

Administration officials had forecast that nearly 500,000 people would enroll this month, according to an internal memo that was obtained by the Associated Press. The memo said that the number would represent a modest start for the ACA.

The Congressional Budget Office has calculated that the exchanges may add 7 million people to the rolls of the insured next year. Experts noted that translated to 39,000 registrations a day during the enrollment period, and that the numbers thus far have fallen far short of that.

“We won’t stop improving healthcare.gov until its doors are wide open, and at the end of the six-month open enrollment, millions of Americans gain affordable coverage,” said the HHS spokeswoman.

President Obama acknowledged problems with the exchanges in an interview with KCCI, a Des Moines TV station.

“I am the first to acknowledge that the website that was supposed to do this all in a seamless way has had way more glitches than I think are acceptable, and we’ve got people working around the clock” on the problems, he told the Iowa station. “We’ve seen some significant progress, but until it’s 100% I’m not going to be ­satisfied.”

An analysis from market research group Millward Brown Digital found that 9.47 million people visited healthcare.gov in its first week with 36,000 enrolling. While visitors dropped to 4.1 million in the second week, enrollment increased to 47,000.

“I will be the first to tell you that the website launch was rockier than we wanted it to be,’’ HHS Secretary Kathleen Sebelius said at Cincinnati State Technical and Community College.

She noted that people still have plenty of time to enroll before the December 15 deadline for coverage slated to begin on January 1.

Sebelius rejected calls from Republican lawmakers for her resignation. White House press secretary Jay Carney said she had “the full confidence of the president.”

Former press secretary Robert Gibbs said on MSNBC that the opening of the exchanges had been “bungled badly” and was “excruciatingly embarrassing for the White House” and HHS. Once the problems are solved, he said, “I hope they fire some people.”