Try to fix cors

app.rb

@@ -5,12 +5,10 @@
 
 configure do
   set :server, :puma
-
-  enable :cross_origin
-  set :allow_origin, ENV['ALLOWED_DOMAIN']
-  set :allow_methods, [:post]
 end
 
+set :allow_origin, ENV['ALLOWED_DOMAIN']
+set :allow_methods, [:post, :head, :options]
 
 helpers do
   def template_file(template_name)
@@ -19,6 +17,8 @@ def template_file(template_name)
 end
 
 post '/contact' do
+  cross_origin
+
   client = Mailgun::Client.new(ENV['MAILGUN_API_TOKEN'])
   renderer = ERB.new(template_file('contact'))
 
@@ -33,12 +33,16 @@ def template_file(template_name)
 end
 
 post '/subscribe' do
+  cross_origin
+
   client = Mailgun::Client.new(ENV['MAILGUN_API_TOKEN'])
   client.post("lists/#{ENV['MAILGUN_MAILING_LIST']}/members", { address: params[:address], vars: '{}' })
 end
 
-options "*" do
-  response.headers['Allow'] = 'POST'
+options '*' do
+  cross_origin
+
+  response.headers['Allow'] = 'POST, HEAD, OPTIONS'
   response.headers['Access-Control-Allow-Headers'] = 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Cache-Control, Accept'
   200
 end