The Commonwealth Bank's mobile app and internet banking services are down for the third time in three weeks, causing fury on social media as millions of Australians are locked out of key banking services. CBA posted to Twitter at 11.45am to notify customers of the outage. "We're aware some of you are experiencing difficulties accessing our services and we're urgently investigating. We apologise and thanks for your patience, we'll provide an update soon." Customers responded with fury: "This happens far too often," said one. "I just had to do the walk of shame out of Woolworths with no shopping in my hands !" said another. A spokeswoman said CBA is urgently investigating the cause of the outage and would update customers regularly via social media and its website. CBA was one of many major financial institutions that experienced a tech crash in mid-June that was caused by a major outage at a little-known technology company Akamai, but the country's largest bank has since had two further outages.