I Have had this problem for over a month.
Finally I have the issue sorted.
TPG only has the lowest security setting for their servers at TLS 1
Check your email program to see what the lowest security setting they will accept
I use thunderbird which needs a minimum security setting of TLS 2
The out going needs the following settings
Server Name mail.tpg.com.au
Port 587
User Name Yours
Authentication No Authentication
Connection Security None
hope his resolves the problem
