Virgin Media O2 has apologised after thousands in the UK reported they were unable to access the internet.
Downdetector, which tracks websites, showed more than 10,000 people reported their broadband was not working on Monday morning.
Users first began reporting issues shortly after 10:00 GMT.
“We apologise for any inconvenience and are working to fix this as a priority,” a Virgin spokesperson told the BBC.
“We’re aware that some customers are experiencing intermittent issues with their services.”
The firm says on its website that together with O2, it represents more than 45 million mobile, broadband, home and phone customers across the UK.
It reported having 5.7 million broadband customers in October 2024.
While user reports to Downdetector have fallen from their morning peak, many Virgin Media customers have continued to flag connectivity issues on social media.
The Student Loans Company has told users on its social media accounts it is among those affected by the outage.
“We’re currently having problems due to a Virgin Media outage, this means we can only give general guidance when you contact us and you might have a longer wait time,” it said in a Facebook post.
“We’re working hard to fix this and we’ll update you when this has been resolved. Thank you for your patience.”
Virgin Media has declined to comment on the cause of the issue.
Its X account told one complainant asking for more information that it “rarely” provides information about root causes to customers.
In January 2024, Ofcom said that Virgin Media was the UK’s most-complained about broadband provider.
It has since improved in Ofcom’s standings and in February 2025 the regulator found it had fewer complaints than TalkTalk, EE and NOW Broadband.