FIX: Force the right encoding when handling email.

app/controllers/admin/email_controller.rb

@@ -84,7 +84,20 @@ class Admin::EmailController < Admin::AdminController
 
   def handle_mail
     params.require(:email)
+    retry_count = 0
+
+    begin
       Jobs.enqueue(:process_email, mail: params[:email], retry_on_rate_limit: true)
+    rescue JSON::GeneratorError => e
+      if retry_count == 0
+        params[:email] = params[:email].force_encoding('iso-8859-1').encode("UTF-8")
+        retry_count += 1
+        retry
+      else
+        raise e
+      end
+    end
+
     render plain: "email has been received and is queued for processing"
   end