The deadline to enroll in health insurance through the Affordable Care Act marketplace at has been extended to 3 a.m. Wednesday, Dec. 18, after widespread reports of technical glitches preventing people from signing up.

The marketplace closed on Sunday. But on Monday, the Centers for Medicare and Medicaid Services (CMS) said it would reopen the marketplace at 3 p.m. “in an abundance of caution, to accommodate consumers who attempted to enroll in coverage during the final hours of open enrollment but who may have experienced issues.”

During the rush to enroll, many consumers were asked to leave their contact information with the call center. These individuals will be contacted by the call center and do not need to return to the website to complete their registration, CMS said.

CMS declined to elaborate on the types of problems that occurred with the website. But on Sunday, consumer advocates called on CMS to extend the deadline for people who encountered problems that prevented them from signing up on the final day of enrollment.

Joshua Peck, a cofounder of Get America Covered, applauded the deadline extension and urged CMS to make sure those who were unable to complete enrollment are aware they now have extra time.

“Nobody should miss the opportunity to sign up for 2020 coverage because of yesterday’s technical problems. CMS must also commit to being transparent about what happened yesterday and on the first day of Open Enrollment, what they did to fix it, the impact it had on enrollment, and what they will do to make sure it doesn’t happen in the future,” said Peck, whose group helps people sign up for coverage.

As of Monday afternoon,’s homepage still featured in large type “2020 Open Enrollment is over.”

A notice about the deadline extension appeared in much smaller type in a narrow blue box near the top of the page.

Plans sold through all meet the ACA’s requirements for comprehensive health coverage, meaning they cover preexisting conditions and “essential benefits,” such as primary care, mental health, and prescription drugs, and limit the total amount members can be required to spend in a year.

Plans are rated by metal level — bronze, silver, gold, and platinum.

Bronze plans offer the lowest monthly premiums but higher deductibles (the amount you pay out of pocket before the plan covers more), copays (a fee you pay to see doctors), and coinsurance (a portion of the bill you may be responsible for even after your deductible is met).

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Gold and platinum plans have the least out-of-pocket expenses and the highest premiums. Silver plans are the most popular option.

Health insurance is expensive, but many people may qualify for an income-based tax credit to help offset the cost of their premium.