its a bit scary and very frustrating when the obvious doesn't happen. Here is how I did it with my TPG emails, Outlook and Microsoft phone so hope it is similar. Under settings, email and app accounts select add account, Advanced setup, internet email and then entered all the fields. Your tpg password, "Mail.tpg.com.au" for incoming and outgoing mail server, account type is POP, and unticked the SSL required boxes for in and out servers and kept the rest ticked. Then select signin (or ok or save)
i returned to the outlook mail icon and it seemed all my emails were downloaded correctly.....not exactly intuitive and took me awhile to find it, so good luck and Happy NewYear to you.
I have had similar problems setting up new phones for my wife and I using Outlook for android. The server settings TPG suggest (which have always worked on PC's and other email apps) don't work, but have found a work around. I believe the Outlook app is using encryption by default and by changing ther server ports to 995 and 465 everything was suddenly OK.