James Jarvis, senior physician executive of Northern Light Health's COVID-19 response, gives a tour of the new vaccine clinic at the Cross Insurance Center on Feb. 1. Credit: Natalie Williams / BDN

The web server that malfunctioned Monday and temporarily shut down Northern Light Health’s COVID-19 vaccine appointment portal believed it was under a cyberattack because of heavy traffic.

In reality, it was high demand for vaccine appointments as more slots opened for those 70 and older and the hospital network prepared to open the Cross Insurance Center as a vaccine clinic for the foreseeable future.

That level of interest in the COVID-19 vaccine is an encouraging sign that shows Maine residents are eager to be vaccinated against the respiratory virus, Dr. James Jarvis, senior physician executive for Northern Light Health, said Wednesday.

Denial-of-service attacks are a common cyberattack in which a website is flooded with inquiries that appear to be high volumes of web traffic. The site becomes overwhelmed and shuts down as a result.

A newly installed web server shut down because of the high level of traffic it experienced at 2 p.m. Monday when a new set of appointment slots opened.

Northern Light has since changed settings so the server doesn’t shut down automatically when faced with heavy traffic, Jarvis said.