@Cappa76 Thanks Joseph TP. Not IOS but windows 11. I don't know what I did, but after a few un-installs and starts over, all seems to be OK and working well

Replaced older TP-link N300 extender with new RE450. Reset old N300 to factory settings before unplugging. Used Tether App to connect new RE450 to Optus Modem/Router successfully. Tether App says all...