Ebay users are reporting issues using the auction website following scheduled maintenance carried out earlier today.
Some users are complaining of log-in failures or problems using the service once they have accessed their accounts.
A spokesperson for the site told the BBC issues had been occurring since around 08:00 BST but added that they were "intermittent".
Site users had been warned in advance that the maintenance would cause disruption, he added.
However the work had taken longer than anticipated, eBay said in a statement.
"We are sorry that intermittent problems with eBay have continued for longer than planned. We are working hard to resolve the issue, and will provide a further update soon," the firm said.