Hello @Drb60 ,

Here are some steps you can follow:
1. Double-check the router's Wi-Fi password: Make sure you are entering the correct password, and that your device can connect directly to the router's Wi-Fi without any problems.
2. Restart your devices: Reboot both your Range Extender and the device you are trying to connect. 
3. Forget and reconnect: On your device, forget the extender's Wi-Fi network and try connecting again by entering the router's Wi-Fi password.

if the extender is not accepting the router's password, please perform a hard reset on the extender. After resetting, reconfigure the extender using the Tether app for best results. You can find detailed instructions here: How to configure Range Extender via Tether APP.