Welcome to the Community!
Your service was indeed affected by an NBN outage. From what I can tell, NBNCo reported an outage at 7:39PM AEDT yesterday (December 16) but was declared resolved at 8:43PM AEDT last night as well. They detected a potential faulty optical node.
It appears that your modem has been connected since 7:47PM AEDT last night. Let us know if you're still having difficulty connecting online.