Kelly Bayer Rosmarin, the CEO of Australia’s second-largest telco Optus, has resigned with immediate effect after a nationwide outage earlier this month which left some 26 million people without phone or internet for 12 hours.

“Having now had time for some personal reflection, I have come to the decision that my resignation is in the best interest of Optus moving forward,” Romarin said in the statement, following a parliamentary hearing on November 17th where Optus executives said the company had no contingency plan in place for an outage of such scale.

Parent company SingTel has announced that CFO Michael Venter will take over as interim CEO.

Appointed in April 2020, Rosmarin also headed Optus through a national scandal that significantly hurt the reputation of the telco. A huge data hack in 2022 exposed the personal data of around 10 million Australians and triggered a class action lawsuit and multiple investigations from regulators.

“We recognise the need for Optus to regain customer trust and confidence as the team works through the impact and consequences of the recent outage and continues to improve,” SingTel Group CEO Yuen Kuan Moon said in a press statement.