"We're aware that some customers are experiencing intermittent issues with their services," they said.
The firm says on its website that together with O2, it represents more than 45m mobile, broadband, home and phone customers across the UK.
It reported having 5.7 million broadband customers in October 2024.
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.