PayPal is experiencing an outage that is affecting most of its members, preventing them from using the online payment service to conduct transactions.
The problem began at around 11 a.m. U.S. Eastern Time and is ongoing, according to a company blog post.
"Almost all our members are having difficulty logging into their accounts and sending or receiving money from PayPal," the post reads.
PayPal didn't immediately respond to a request for comment.
There are more than 87 million active PayPal accounts in 190 markets and 24 currencies worldwide.
A massive system outage at PayPal is the last thing parent company eBay needs. In the third quarter, PayPal, increasingly important to eBay's financial health, grew its revenue 22 percent to US$838 million year-on-year, while the eBay online marketplace registered revenue growth of only 3 percent.
Revenue for all of eBay inched up 1 percent, eBay said last week. PayPal accounted for 37 percent of eBay's overall revenue, up from 31 percent in 2009's third quarter.