SYDNEY, Nov 8 (Reuters) - Millions of Australians were left without a phone or internet connection on Wednesday after the country's second-largest telecommunications provider experienced an unexplained nationwide outage. "Our teams are working urgently to restore services. The government had sought further information from Optus including when they expected to restore services. Melbourne's train networks were forced to shut down for about 30 minutes due to the outage, resulting in delays during the morning rush, media reported. A cyber breach last year hit Optus, exposing personal details of millions of its customers, including their home addresses, driver licence and passport numbers.

---

Persons: telco, Michelle Rowland, Rowland, Renju Jose, Praveen Menon, Stephen Coates Organizations: SYDNEY, Optus, Singapore Telecommunications, Commonwealth Bank, CBA, Reuters, Federal Communications, ABC Radio, Thomson Locations: Sydney