Updated July 17, 2026 — 5:54pm,first published 10:57amMillions of people were knocked offline by Telstra’s mobile network failure last week, chief executive Vicki Brady has revealed, confirming the outage hit a scale the telco did not disclose at the time.The admission that approximately 45 per cent of the network that has more than 25 million mobile devices on it went down at its peak dovetailed with confirmation that more than 400 Triple Zero calls were not transferred to another network as a backup. Telstra’s group owner of end-to-end service performance and resilience, Gerard Tracey, conceded the outage would not have occurred if the company had replaced its old server.AAPDuring a Senate hearing into last week’s major outage, a senior Telstra executive conceded on Friday that the entire disaster would have been averted had the company replaced an ageing server that cost just $30,000.Telstra’s Gerard Tracey told Friday’s Senate inquiry hearing that newer equipment would have stopped last week’s mass network outage from occurring, in the clearest concession yet from the company that the failure was avoidable.Asked whether a newer piece of hardware operating as intended would have prevented the fault, Tracey said: “A newer piece of hardware operating in the same design that we intended to, the issue wouldn’t have happened.”The admission came after chief executive Vicki Brady had twice declined to answer the same question directly, telling the committee it would be addressed by Telstra’s ongoing investigation.Tracey’s answer is the first clear confirmation from Telstra that replacing the ageing server, which this masthead first reported cost about $30,000 to replace, would have avoided the outage that cut hundreds of people off from Triple Zero and disrupted trains and eftpos terminals in several states.The failure of the 15-year-old device was the product of several errors that compounded. Telstra received multiple warnings about a problem with the device that could cause it to set its time back 1024 weeks, but did not act on them because they were seen as irrelevant. Then, Telstra fixed a connection issue in a way that caused the first problem to resurface when the device was restarted.That change was never documented and, when a technician restarted the device to fix yet another issue with backup power, the device wound back to 2006 and an error spread through the network kicking off phones that were showing the correct time.“That is clearly unacceptable,” Brady said. “If maintenance work can trigger this kind of outage, it suggests our controls were not good enough.“We are accountable for that, and our external expert investigation will address why that design change was not documented, why the software update was not completed, and what needs to change in our controls so known risks are captured, prioritised and closed before they can affect customers.”Telstra chief executive Vicki Brady has conceded the company had received warnings about the device that caused the error.AAPThis masthead previously reported the device in question was a SyncServer S300 but Telstra on Friday said, based on its investigations so far, that the model was an SSU 2000, made by the same US semiconductor company Microchip.The device, which had been bought in 2011 but which Telstra said was still supported by its manufacturer, has since been replaced.Brady said that, at its peak, last week’s outage affected approximately 45 per cent of all calls and data sessions on Telstra’s mobile network. The company initially said that probably only thousands of customers had been affected. It has said all of its communications were accurate at the time, but that the outage slowly got worse.The 45 per cent figure is Telstra’s first public disclosure of the scale of the outage at its worst point.The hearing also drew out the human cost. During the outage, about 3200 Telstra customers reached Triple Zero only because their phones, unable to connect to Telstra at all, had already switched to Optus or TPG — an industry fallback known as “camp on”. Those calls went through.A further 604 were not so lucky: their calls failed on Telstra’s network first, forcing the phone to search for a rival network from scratch. Tracey said only 172 of those callers held on long enough for the fallback to work. The other 432 never got through. “The rest of them failed, and the users did not wait long enough for the camp-on process to kick in,” he said.Telstra’s satellite messaging service, which it markets as coverage beyond the mobile network, also buckled. Tracey said authentication for the satellite service still depends on Telstra’s network, so “there was a high failure rate attached there as well”.Senator Sarah Hanson-Young.Alex EllinghausenTelstra conceded it has no way of knowing whether medical alert devices failed silently during the outage, since its welfare check process covers only Triple Zero calls that were placed and failed. Brady said the SIMs inside such devices appear on Telstra’s network as ordinary data connections. “We can’t identify them on our network,” she said.Senator Sarah Hanson-Young said the committee knew of a woman who found her elderly mother on the kitchen floor because her distress device had not worked. She accused Telstra of having several chances to fix the problem that caused the outage and failing to act.“When you’re banking huge increases in profit, there are more outages, less reliability for people to access and use their mobile phone,” she said. “I don’t think it washes to go around telling people that your system’s resilient. It’s clearly not.”The company has written to 8.8 million consumer and small business customers but ruled out automatic compensation.Chief financial officer Michael Ackland said just over 8000 claims had been lodged, and a little over $100,000 paid so far, entirely in bill credit. The largest claims are yet to be processed.Brady said she had not commissioned any analysis of what the outage cost the economy.The Business Briefing newsletter delivers major stories, exclusive coverage and expert opinion. Sign up to get it every weekday morning.From our partners