A combination of high demand and technical glitches seemed to overwhelm the online system early in the day. Federal and state officials were working to address the problems, which led to long waits on government websites and a federal call center.

Health and Human Services spokeswoman Joanne Peters said that more than 1 million people had visited HealthCare.gov in the last day - five times more users than have ever been on the Medicare.gov at one time.

Kimberly Shockley - logging in from Houston, Texas - and Mike Weaver, who lives in rural southern Illinois, ran into similar glitches: They could not get past the security questions while trying to set up their personal accounts through healthcare.gov.