The American Express homepage (home.americanexpress.com) was unavailable for over five hours today. During that entire time the page responded with an HTTP 404 error (page not found). Visitors to the homepage were met by a simple text message: “File not found.”

The problem lasted from 05:47 a.m. to 10:52 a.m. Central European Time (11:47 p.m. yesterday to 04:52 a.m. today US Eastern Time).

This is the first time in 2008 that the American Express homepage has had any downtime. A previous report from Pingdom comparing the availability of credit card company websites showed the American Express homepage having 100 percent uptime during the period leading up to Christmas.

This appears to have been unplanned downtime. If American Express were performing planned website maintenance, a maintenance message should have been shown on the homepage.