Phone users across the UK complained they didn't receive the Government's emergency alert test on Sunday.
And now mobile network provider Three has issued a statement confirming some of its customers were affected.
The Government was trialling its new emergency alert system, which will be used in future to warn people about dangerous situations, such as floods or during terror attacks.
Read More: Warning of more toilet roll shortages as new law takes effect
It was set to be tested out nationwide on all mobile phones that are compatible with 4G and 5G.
However some people were left confused as they failed to receive the alert - with some saying it is down to their network provider.
And now Three has addressed the claims.
A Twitter post read: "We're aware that a number of customers have not received the test alert. We're working closely with the government to understand why and ensure it doesn't happen when the system is in use."
Other people may not have received the alert due to not being connected to 4G or 5G.
The alert relies on towers that go up to 4G or 5G, so if you were only connected at 3G at the time the test alert was sent, then your phone would not have been capable of receiving it.
Your phone could also have the emergency alert settings switched off. Despite being an automatic alert, it is possible to switch them on iPhones and Androids by going into settings, typing 'emergency alerts' into the navigation bar and switching the 'Extreme Alerts' button to on.
READ NEXT:
- First £301 DWP cost of living payment will start to arrive within days
- DWP benefits could be slashed as energy bill repayments freeze comes to an end
- Month-by-month guide to when you can expect all of this year's cost of living payments
- Sisters 'at the end of their tether' after feeling harassed by British Gas following Morpeth mum's death
- Map of England's most dangerous beaches to swim at - including popular North East spot
