Try the following solutions:
If a WiFi device is used, make sure your WiFi device has connected to the extender’s network, and not that of your router. If the WiFi extender is not set up, please connect to the default network (BrosTrend_EXT) of the WiFi extender. If the WiFi extender has been set up, connect your WiFi device to one of the extended networks. Make sure that the Mobile Data (if any) function is disabled.
If a computer is used, connect your computer to the WiFi extender via an Ethernet cable. In this way, your computer is connected to the WiFi extender physically. Make sure that your PC has no Internet connection during its setup.
Verify that re.brostrend.com or 192.168.0.254 is correctly entered in your browser.
Use another WEB browser and try again.
Reboot or reset the extender and try again.