Inside MS Outlook 2019, I tried changing from POP to IMAP, and now I get error:
"We couldn't connect to the outgoing (SMTP) server. Please check the outgoing (SMTP) server settings and try again."
I changed them as per OptusNet directions at:
Access your optusnet.com.au email with IMAP - March 2023 - Mailbird

When that didn't work, I deleted my optusnet account from MS Outlook 2019, then went to Control Panel, Mail and restarted setting up account.
However this time I got an error
unknown error 0x80040119
which I googled on and it stated:
"The most likely issue that will trigger the outlook unknown error 0x80040119 is an inconsistent Outlook (. PST) file. If this file is corrupted, you might not be able to use the server to send and receive e-mails."
However, I again tried scanpst, it said errors, I then repaired... but I then ran scanpst a second time, and it still there were errors. So scanpst doesn't repair errors despite saying it does. In other words, scanpst has a bug in it, saying there aren't errors when there are errors.
Can you suggest a more powerful PST repairer?

I googled and tried Wondershare Repairit for Email, but it also had an error running.