It's been a while since I have messed with Outlook however I think the auto config works by simply entering your Optus email and password. Check your username and password is correct by logging into webmail before you run Outlook.
my problem is the same as
having trouble connecting to optus exchange. my Outlook 365 connected to my gmail account, but is also showing my optus email, but will not load mail in inbox or sent folders
a previous blog in December 2019
I am experiencing the same problem. I can't use Office 2010 or 2013 On my Desktop Win-10 PC anymore. I upgraded to Office 365 a week ago and I can only send emails. I can only access emails though my Optus Webmail account. Microsoft has had REMOTE access to my PC today twice. I can still only send emails and not receive new ones.
I was on the phone today with Optus regarding the POP3 & SMTP settings and nothing is working. Can anybody come up with ideas on how to solve these issues.