set up smart plug and it works great from the app and via voice from one echo. Other echos, dots, plus, and standard second generation do not work. They do not seem to recognize it exists.
Have tried to rediscover, device not found
Hi robert52, welcome to our Forum!
I am sorry your having this Problem let's see if these steps solve the Problem.
Connect your Alexa device to the same Wi-Fi network as your smart home device. If you've changed your Wi-Fi password recently, you can modify the Wi-Fi settings in the Alexa app: Select Devices "". Navigate to your device. Select Change next to Wi-Fi Network. Follow the on-screen instructions. Use your computer to turn on SSDP / UPnP in your router settings. Contact your router manufacturer for help.
Note: Some smart home devices only work with 2.4 GHz Wi-Fi band connections. Check with your smart home device manufacturers for more information. For the Amazon Smart Plug, try changing your Wi-Fi band connection. Also see here for more help.