If you’ve bought a new iPhone5 and are struggling to get your personal hotspot working, or if you’ve recently reset all phone settings (maybe to troubleshoot iPhone5′s battery drain issues) then try this.
If your APN (Access Point Name) is set to telstra.wap change this to telstra.iph. Then if your personal hotspot is on, turn it off then on again and see if that fixes your problem.
You don’t need to enter anything in the Username or Password fields as shown on the left.
Let us know how you go.