American Express credit services systems are reported down in multiple locations around the United States, and possibly worldwide.
The reported outage began at approximately 1 pm ET.
Customers reported via Twitter on Thursday that AMEX credit cards were declined at points of purchase, online, and that it was impossible to get through to AMEX Customer Service by phone.
AMEX gift cards were reportedly also affected.
Nearly 3,000 (2,736) customers were affected, according to the Downdector website, which reported that outages in the United States were primarily in New York and Chicago.
Outages were also reported in the UK, and possibly in Canada as well.
American Express suffered similar problems about a week ago, and this past August as well.
There was no immediate word on what was causing the disruption, and the company has not offered any explanation or comment thus far.