If you have a harmony hub and it is not working, it is not you or alexa. It is a logitech issue.
https://arstechnica.com/gadgets/2018/12/logitech-firmware-update-breaks-locally-controlled-harmony-hub-systems/Many users of Logitech's Harmony Hub smart home hub and remote were recently met with a nasty surprise. The device's latest firmware update, version 4.15.206, reportedly cuts off local access for Harmony Hubs. As a result, many users who created home automation and smart home systems using third-party APIs haven't been able to control many, and in some cases, all of their connected IoT devices.