I'm back again. Let's troubleshoot the email account from your end first.
In times lost in history, before GUIs and Windows we had to send emails using the protocol typed in a terminal. To test the account at the server by sending an email, and checking all of the return codes, start telnet as follows in a terminal/DOS prompt window (Windows 10 needs to enable telnet - https://www.rootusers.com/how-to-enable ... windows-10
It still works today...(use your state):
telnet smtp.nsw.exemail.com.au 25
(it will reply with code 220 and a dragon message)
(it should reply with code 250 and your Exetel IP address)
MAIL FROM: your-exemail-email-address-in-full
(250, we hope)
RCPT TO: target-email-address
(250 accepted, we hope)
(354, and instructions)
type the test message now, end with newline
type . (full stop by itself) and newline
(250 ok, and the ID)
The problem in the first post is commands out of order. I don't know why Outlook is getting it back to front, but the method described will enable you to check your account, and receive an error message if any step is wrong.