Optus sent critical Triple Zero failure notifications to a misspelled Telstra email address during September’s fatal network outage, repeating communication errors that delayed emergency response coordination, Senate inquiry documents reveal.

The telecommunications provider incorrectly addressed its 3:17pm notification on September 18, with the email not initially received because it was sent to an incorrectly spelt address.

Optus discovered the error after calling Telstra and forwarded the email to the correct address at 3:26pm.

This marks the second known email error during the incident, following October’s revelation that Optus had also sent government notifications to an outdated account.

The September 18 outage prevented more than 600 emergency calls from connecting across three states, resulting in fatalities.

Telstra, which handles 32,000 emergency calls daily, couldn’t detect the failures because “calls were failing before reaching Telstra’s network, and hence, before reaching the emergency call person.”

The company only learned the full extent through Optus’s media conference the following day.

A separate Wednesday outage affected Victoria’s Frankston and Mornington Peninsula regions after suspected vandals cut a fibre cable.

Services were restored by late morning without Triple Zero failures.

The Albanese government responded by introducing legislation requiring Telstra, Optus, and TPG to provide satellite-based mobile coverage nationwide by December 2027, ensuring Australians get signal “almost anywhere they can see the sky,” according to Communications Minister Anika Wells.

The Senate inquiry continues, with its next hearing scheduled for December 9.