METAR URL is broken
The METAR URL https://www.aviationweather.gov/adds/dataserver_current/httpparam
is returning 404.
A quick-fix is to substitute the URL https://aviationweather.gov/cgi-bin/data/dataserver.php
which is functionally equivalent (takes exactly the same query string parameters and returns the same response).
A better solution might be to migrate to the new API. Reference: https://aviationweather.gov/data/api/