Herald Sun | Optus customers hit by mobile phone network outage Herald Sun THE cause of Optus' mobile outage has been revealed after Australian customers were temporarily unable to make or receive calls on their mobile phones today. The telco giant confirmed the outage in a tweet today, which stated: “We're aware of an issue ... Optus customers unable to make or receive calls during network outage Service interruptions impact Optus mobile customers Network Outage Leaves Optus Customers Unable To Make Or Receive Calls |