The HERE service has been updated but Qt has not updated its plugin.
The main changes are:
The app_id and token is only necessary when using the HERE SDK, in the case of Qt the apiKey must be used.
The HERE services url has had the following changes:
Use https (it was previously accessible through http but not now).
The previous host had the format X.api.here.com but now it is X.ls.hereapi.com.