diff --git a/config/environments/production.rb b/config/environments/production.rb
index c2f98c8..d4b85cd 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -82,7 +82,7 @@
   config.action_mailer.default_url_options = {
     host: ENV['ACTION_MAILER_DEFAULT_HOST']
   }
-  config.action_mailer.asset_host = config.action_mailer.default_url_options[:host]
+  config.action_mailer.asset_host = "https://#{config.action_mailer.default_url_options[:host]}"
 
   # Ignore bad email addresses and do not raise email delivery errors.
   # Set this to true and configure the email server for immediate delivery to raise delivery errors.