Telstra customers across the country are reporting the provider's mobile network has crashed, potentially leaving millions of Australians unable to make phone calls or access the internet.Outage detection site Downdetector.com shows a large spike in reports beginning about 5am AEST.Downdetector.com shows a huge spike in Telstra outage reports shortly before 6am. (Supplied: Downdetector.com)Users of other mobile providers that operate on Telstra's network, including Boost, Aldi, Tangerine, Belong and Everyday Mobile, are also reporting outages.However, the outage does not appear to be affecting all the telco's customers, with many reporting on social media that they are still able to make calls, access the internet, or both.Calls to Triple Zero (000) should be unaffected by the outage, with calls rerouted to use other providers' mobile networks.A Telstra spokesperson told the ABC the company is looking into "an issue affecting some mobile calls and data connections"."If you're having trouble connecting, try again as it may work on a retry," the spokesperson said."We're on it and will share an update as soon as it's fixed. Thanks for sticking with us."Telstra operates Australia's largest mobile network, providing about 24.9 million retail mobile services as of June last year.The company was fined more than $3 million in 2024 for a network outage that prevented customers from calling Triple Zero.