There can be a case that you fail to fix the extender’s errors even after attempting several resolving tips. In that case, you must prefer to use the reset process. So, to do that, find the reset button on the Linksys RE6400 setup and press it. Usually, it is a tiny button or hole with the word "Reset" in it that needs to be accessed with a pin or paperclip. Make sure the RE6400 extender is turned on. For around 10 seconds, or until the device's LED lights begin to blink, press and hold the reset button. To start the reset procedure, release the button. The settings of the RE6400 will thereafter be reset to their factory default after a rebooting process. You must configure the RE6400 new from scratch after resetting the device as the older configured settings will be discarded now.