Last October, the exchange pulled its list of doctors and published an updated directory the following month.
Since policies took effect last month under the new healthcare law, people have complained that doctors won't accept their insurance even though they're listed online by Covered California and their health plan.
"While the combined provider directory was a useful service for many consumers, some enrollees located physicians thought to be in their plan, and subsequently discovered they were not," the exchange said in a statement.
The state said people still have time to switch insurers before open enrollment ends in late March.
The California Medical Association told the Times last week that it found flaws in the directory, mostly because of inaccurate information from insurers. Meanwhile, insurers have blamed some doctor's offices for mistakenly turning patients away.
Micah Weinberg, a health policy expert at the Bay Area Council in San Francisco, said this blame game could put a brake on recent momentum.
"One of the things that worries me a great deal about all this is that it runs the risk of setting consumers, doctors, health plans and Covered California against each other," Weinberg said.
Besides problems with the online directory, Covered California continues to grapple with customer service woes. The exchange said the average wait time to speak with a customer representative was 52 minutes last week. It plans to hire 350 more people to answer calls.