The broadband service run by mobile firm Orange is experiencing a "major" national outage.
Several users have complained that they have been unable to use their connection since Monday afternoon.
A spokesperson for the company said the fault on the service, formerly known as Wanadoo, was caused by a "network equipment failure".
Orange said they were working to fix the problem but there is no indication when a normal service will resume.
The BBC news website was alerted to the fault by a reader who had been unable to connect to the internet for the last two days.
Other users have since confirmed the problem.