The Obama administration's health care website is stumbling on deadline day for sign-ups.

Visitors to HealthCare.gov on Monday morning saw messages that the site was down for maintenance. At times the were also directed to a virtual waiting room—a feature designed to ease the strain on the site during periods of heavy use.

Administration spokesman Aaron Albright says the website undergoes "regular nightly maintenance" during off-peak hours and that period was extended because of a "technical problem." He didn't say what the problem was, but a statement from the Health and Human Services Department called it "a " unrelated to application volume.

Albright said consumers seeking to sign up will be able to leave their email and "will be invited back when the system is available."

© 2014 The Associated Press. All rights reserved.