@Banno Hello, Did you have any power outage or firmware update failure on this extender, it looks some hardware defect on the extender. You could try a different power socket, and if still no help,...

@Ronsensei Hello, The speed that RE gets directly from router is quite important, as this is a single band RE, please test what is 2.4Ghz Wi-Fi speed from Router at the Same Location of RE ? Please...

@HariM Hello, If RE605X failed to detect your 5Ghz, here is an FAQ that you could give it a try, please change to router /Nokia wireless antenna's 5Ghz channel to 36/40/44/48. Why my Range Extender...

@Jus Hello, How about the LEDs Status on this range extender? If signal Led on 855RE is off, you could do a factory reset tp-link range extender and resintall it through Tether app or Web page Reset:...

@Adifponnu6544 Hello, Kindly check my reply on your post in another thread: https://community.tp-link.com/en/home/forum/topic/226420?replyId=582410

@2385 Hello, 1>Please verify your Wi-Fi password by forgetting your Wi-Fi network on cell phone first : Go to Settings-> WiFi on your phone, Tap (or Long press the router's WiFi name ->Forget /...