OSM geocoding is associated with a proper user agent

config/initializers/geocoder.rb

 Geocoder.configure(
   # geocoding options
   # timeout: 3,           # geocoding service timeout (secs)
-  timeout: 10,
   lookup: :nominatim,     # name of geocoding service (symbol)
-  language: :fr           # ISO-639 language code
+  language: :fr,          # ISO-639 language code
+  http_headers: { 'User-Agent' => 'agendadulibre.org' }
 )