EE customers in the UK are experiencing blackspots meaning they are unable to make calls or use data.
The site, which tracks outages across popular services, reports that 68% of those affected are struggling with their mobile data connection.
A poor 11% are just reporting a ‘total blackout’.
The most heavily-affected areas, according to DownDetector, are London, Birmingham, Manchester and Sheffield.
An EE spokesperson confirmed that these were isolated incidents and not as a result of a larger outage with the network.
The spokesperson told Metro.co.uk: ‘Some customers are experiencing issues using their mobile data.
‘We are working quickly to fix this and customers can still make calls and send texts. We’re really sorry for the inconvenience caused.’
In the meantime, customers were quick to call out the network provider on Twitter for their dropped connections.
EE hasn’t responded on social media, or acknowledged the problems this morning as yet.
However, it does offer a service checker page on its site that customers can use to find out status in their local area.