For customers experiencing any issues with their NBN service, we recommend the best thing to do first is check if there's an outage on the NBN network.
We have created this article that can guide you on How to Check for NBN Network Outage
If there are no known outages in your area, customers can proceed with the troubleshooting steps indicated on this link : Troubleshooting No Internet Connection
If the issue is particular with the Wi-Fi, we have also created this article that may help resolve the issue : Wi-Fi troubleshooting steps - No Internet/Connection
In your case, the issue has been resolved by manually configuring the router settings.
Let us know should you need further assistance.