Someone following the news closer please fact-check me, but AFAIK, the chain of events:

- The Optus network (the second largest telco network in Australia) went down

- Optus executives initially couldn't coordinate anything because they were... all on Optus

- The network outage lasted ~14 hours

- The network outage effected triple-zero, the country's emergency number, because Optus was rebooting towers and causing phones to still connect to them so they can't fallback to another carrier to dial 000

- After the network is finally back up, Optus blamed "a 3rd party" that caused the outage

- The "3rd party" was then turned out to be Singtel - Optus' parent company

- Singtel issued a statement to basically say Optus was wrong

- Optus then issued another statement saying the outage was caused by them using default configuration files on some of their Cisco routers

- The Australian senate summoned the Optus CEO for a hearing

- Here we are, the CEO resigned

EDIT:

To add more context, just over a year ago (in Sept 2022), Optus, under the same CEO's leadership, had a massive data breach: https://en.wikipedia.org/wiki/2022_Optus_data_breach

This seems like it was driven by Singtel in an effort to just make everyone forget about the recent issues. Namely, a massive leak of customer PII, and a 14 hour outage of their core networks.

Optus's issues are long running. My understanding is that they're largely driven by Singtel's desire to keep cutting everything to the bone.

I've got no idea about Rosmarin's effectiveness as a CEO.

Sure, it didn't help that she was a no-show for most of the outage, and when she did do interviews the responses were weak or not exactly confidence building that they knew what the problem was or how to fix it.

Even still, I don't see throwing a new CEO at it is going to result in any meaningful change while Singtel are still the owners, and there's no legislative changes to protect consumers and critical infrastructure.

Large parts of the business are driven entirely on short-term metrics which can be fiddled with to hide problems. The use of contracting firms (both onshore and off) to manage/build/maintain what should, for a Telco, be their core strengths only seems to make this worse.

Opinion based on few anecdotes, but I'm sure the blame lies with Singtel, especially given that there was initial finger-pointing that was then retracted. Classic "protect the castle, sacrifice the farmhouse (administrator)".

I've heard from multiple sources that Optus in Australia is somewhat of a cash cow for Singtel in slightly undercutting Telstra's exorbitant pricing whilst absolutely minimising support and administrative costs. The 2022 security breach[0] being a potential example of a symptom.

Interestingly the article specificies this as the cause:

On Friday, Optus confirmed the outage was due to a configuration issue with more than 90 Cisco routers, which could not cope with changes to routing information supplied from Singtel Internet Exchange (STiX) after a routine software upgrade.

[0]: https://en.wikipedia.org/wiki/2022_Optus_data_breach

She did an absolute train wreck of a radio interview about 6.5 hours into the outage. It's a 6 minute listen, available here - https://www.abc.net.au/listen/programs/sydney-mornings/optus...

Optus has been a basket case for many years, and was only made worse by appointing a number of ex banking executives whom don't understand the role Optus' products play in their customers lives.

Lose all your data through an unauthenticated API endpoint? She’ll be right mate

Ten hour outage? Don’t let the door hit you on the way out

The former seems like a much bigger problem in my mind but maybe that’s my bias showing