Hi Knightmayre,
Hopefully this issue has been resolved for you already, but if you still need assistance with this, it could be a misalignment of the password. Customers can resolve this by logging into http://telstra.com.au and changing the password.
The following links provide information about the transfer to the new mail platform, including how to tell which one your mailbox is hosted on.
Let me know how you go.
- Shelly