Software, Design Defects Cripple Health-Care Website

Six days into the launch of insurance marketplaces created by the new health-care law, the federal government acknowledged for the first time Sunday it needed to fix design and software problems that have kept customers from applying online for coverage.

The Obama administration said last week that an unanticipated surge of Web traffic caused most of the problems and was a sign of high demand by people seeking to buy coverage under the new law.

But federal officials said Sunday the online marketplace needed design changes, as well as more...