The department has not said how many of those people successfully enrolled in coverage.
The window to enroll will remain open for six months, and consumers have until Dec. 15 to sign up for coverage that begins Jan. 1 — the earliest date new plans would take effect.
Healthcare.gov displayed basic error messages Tuesday that said the site was unavailable, but on Wednesday afternoon, the site redirected to a "holding page" that allowed visitors to hold their place in line.
Wait times for the enrollment call centers have also improved, HHS said.
Administration officials have repeatedly acknowledged that "glitches" would be an issue when launching the enrollment process for new health insurance marketplaces.
Healthcare.gov is the portal to compare coverage options in the 34 states where the federal government is operating the new insurance marketplaces.
In addition to the overloaded site, many visitors to the site were unable to complete the first step of signing up for an account. The site rejected users' answers to security questions.
HHS said that problem was a result of heavy traffic, not a programming error.