@StuartF Having the same problem, it's more looking like it's Optus's issue..... I tried speaking to them earlier and they told me to try TP-Link support, which is sounding like TP-Link would like to...

@Newbie2tp I have the same issue too, however when I try to set up my Tapo and Kasa plugs on my phone's hotspot, it seems to work fine, which is definitely not ideal as you don't want your hotspot on...