The Centers for Medicare and Medicaid Services (CMS) on Wednesday announced that those who started their health insurance sign-ups on but had difficulties could still enroll — but they must do so by Tax Day, April 15, or face a non-compliance tax penalty at the end of the year.

"For those in line on the 31st [of March], we encourage consumers to finish the process as soon as possible. They must complete their enrollment by no later than the 15th [of April] for coverage this year," said Aaron Albright, CMS spokesperson.

Several state-operated Marketplaces have already announced similar grace-period deadlines.