Hi Dobby,
ATO outages due to scheduled maintenance usually generate this application error whilst the ATO's systems are down, so I would encourage you to try later this morning to see if you get the same BAS lodgement error. That being said, if you try and still receive the same error I would like you try a small troubleshooting step.
As the error may stem from the web browser even when all connections are set up correctly, I would advise to check our browser troubleshooting guide here. This includes clearing cache and cookies, whilst also trying different web browsers e.g. Firefox or Chrome to try submit the BAS through QuickBooks again.
If still unsuccessful, I would kindly ask you reach out to our friendly support staff by clicking here so we can confirm the ATO connection is active, and troubleshoot further.
Hope to hear this gets resolved,
-Steven
