Slave email account - "Relaying denied. Proper authentication required."

[qak]

We've had NBN connected, and I've since noticed that some email forwards I had set up are not working, and emails I send are mostly bouncing with the "Relaying denied. Proper authentication required." The main account is OK, this error messages relates only to my slave email account.

These were all working fine a couple of weeks ago (I've had the main and slave accounts for many years)

I haven't changed anything at my end, why would I be getting this now & how do I fix it? I'm using Outlook 2010 (and so is the main account that has no issues).

[qak]

I solved by using the steps in this previous forum post:

https://community.tpg.com.au/t5/Broadband-Internet/TPG-does-NOT-work-with-Outlook/td-p/1538/page/3

I'm not sure if something changed at TPG to require me to change settings, but updating my username to exclude '@tpg.com.au' and ticking SMTP requires authentication solved the problem.