So like me you've looked everywhere to solve the provisioning error message on your Alexa app when trying to connect to your Amazon smart plug.
I was on the verge of returning these plugs to Amazon when I stumbled across the simple fix. Amazon take note!
The problem is your router, Most modern routers are now supplied with a dual band function straight out of the box, In layman's terms this means your WiFi can be broadcast on two different frequencies (2.4Gz and 5.0Gz)
These smart plugs do not connect on a 5.0Gz frequency and this needs changing in your router settings.
Technophobes have no fear, this is a simple process...
In your internet browser, preferably on a computer attached to your home network, type in your router address, this will probably be 192.168.0.1 (can also be done on a smart phone)
The login details username/password can be found on the underside of your router (If not then contact your ISP for the login)
Now simply click on WiFi settings and untick the 5.0gz box and click the 'apply' or 'save' button.
It's now very important to restart your router for the changes to take effect.
Hey presto!! Your plug will now connect to your home network.
Amazon this information should be clearly setout in your instructions. It would have saved me hours of frustration.