Wavlink’s primary device needs to be positioned in the middle of your house, meaning that other supporting devices need to be in WiFi dead zones. Since these are the places where these devices perform best, it is believed that these are the optimal locations for them. However, in addition to choosing the ideal places, you also need to ensure that the Ethernet wires and ports are working. They are also necessary for the transmission and reception of signals. You must so only use the original Ethernet cables that came with the package in order to maintain connectivity. Furthermore, those cables cannot be broken.
After connecting the compatible devices and considering these points, if you still experience a Wavlink extender login error, there is definitely a problem with the connection. Thus, make sure to double-check those points and try connecting them once more. In addition, check that the power sockets and cables into which the devices are plugged are in good working order. Try rebooting each supporting device once if you are still having trouble connecting them.