Failed to load resource 401 unauthorized only with Safari - ruby-on-rails

Question

I'm found an interesting problem in my app.
I'm using Rails 3 with ruby 2.0. I already have a production server where my app is running and another staging server. I'm configuring a new better one but I have a problem only with Safari.
Redirected to http://ip.server/
Completed 302 Found in 201.7ms (ActiveRecord: 0.0ms)
Started GET "/" for my.ip at 2014-10-13 08:17:18 +0200
Processing by DashboardController#index as HTML
Completed 401 Unauthorized in 1.2ms
Started GET "/user/sign_in" for my.ip at 2014-10-13 08:17:18 +0200
Processing by Devise::SessionsController#new as HTML
Rendered application/_field_errors.html.erb (0.0ms)
Rendered application/_field_errors.html.erb (0.0ms)
Rendered devise/sessions/new.html.erb within layouts/devise (2.3ms)
Completed 200 OK in 5.5ms (Views: 3.8ms | ActiveRecord: 0.0ms)
When I check on the network tab, I can see this:
Fail to load resource: the server responded with a status of 401 (unauthorized)
At the beginning I thought my problem came from Devise but then I checked on Google and find that:
cross browser problem
I tried on Chrome and it works. I tried also without AdBlock or with the private navigation but it still not working with Safari.
Edit:
I did 2 requests, one coming from Chrome and the second one from Safari. The only difference is this line:
WARNING: Can't verify CSRF token authenticity
Edit 2:
I've commented the line protect_from_forgery on my ApplicationController.rb and finally this error (about CSRF) wasn't responsible for my problem.
Here my stacks when I try with Chrome and with Safari.
With Chrome:
Started POST "/user/sign_in" for my.ip at 2014-10-14 13:27:51 +0200
Processing by Devise::SessionsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"c86MNR4MCSbQWJiAjkGtgfgPMg5YirG1tqf/2vqdBWc=", "user"=>{"email"=>"test#example.com", "password"=>"[FILTERED]", "remember_me"=>"0"}}
User Load (0.4ms) SELECT `users`.* FROM `users` WHERE `users`.`email` = 'test#example.com' LIMIT 1
(0.1ms) BEGIN
WARNING: User#current is nil, are you including SentientController on your ApplicationController?
(0.3ms) UPDATE `users` SET `last_sign_in_at` = '2014-10-14 11:26:45', `current_sign_in_at` = '2014-10-14 11:27:51', `sign_in_count` = 52, `updated_at` = '2014-10-14 11:27:51' WHERE `users`.`type` IN ('User::Admin') AND `users`.`id` = 1
(26.1ms) COMMIT
Redirected to http://server.ip/
Completed 302 Found in 135.6ms (ActiveRecord: 0.0ms)
Started GET "/" for my.ip at 2014-10-14 13:27:51 +0200
Processing by DashboardController#index as HTML
User Load (0.4ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 1 LIMIT 1
server.ip Rendered dashboard/index.html.erb within layouts/application (2.5ms)
Rendered application/_header.html.slim (57.6ms)
Rendered application/_sidebar.html.erb (48.1ms)
Rendered application/_page_header.html.slim (2.0ms)
Rendered application/_flash_messages.html.erb (0.5ms)
Rendered application/_footer.html.erb (0.8ms)
Completed 200 OK in 137.5ms (Views: 122.9ms | ActiveRecord: 5.1ms)
With Safari:
Started POST "/user/sign_in" for my.ip at 2014-10-14 13:27:58 +0200
Processing by Devise::SessionsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"TWKhSxus5q46H9sZdEvMnzD52r0zA5phw/Pv7K+NKuY=", "user"=>{"email"=>"test#example.com", "password"=>"[FILTERED]", "remember_me"=>"0"}}
User Load (0.4ms) SELECT `users`.* FROM `users` WHERE `users`.`email` = 'test#example.com' LIMIT 1
(0.1ms) BEGIN
(0.3ms) UPDATE `users` SET `last_sign_in_at` = '2014-10-14 11:27:51', `current_sign_in_at` = '2014-10-14 11:27:58', `sign_in_count` = 53, `updated_at` = '2014-10-14 11:27:58' WHERE `users`.`type` IN ('User::Admin') AND `users`.`id` = 1
(24.8ms) COMMIT
Redirected to http://server.ip/
Completed 302 Found in 138.2ms (ActiveRecord: 0.0ms)
Started GET "/" for my.ip at 2014-10-14 13:27:58 +0200
Processing by DashboardController#index as HTML
Completed 401 Unauthorized in 1.2ms
Started GET "/user/sign_in" for my.ip at 2014-10-14 13:27:58 +0200
Processing by Devise::SessionsController#new as HTML
Rendered application/_field_errors.html.erb (0.0ms)
Rendered application/_field_errors.html.erb (0.0ms)
Rendered devise/sessions/new.html.erb within layouts/devise (2.2ms)
Completed 200 OK in 5.2ms (Views: 3.7ms | ActiveRecord: 0.0ms)

Answer 1

Problem solved. It was not at all coming from my app but from my DNS redirection. I put an simple web redirection for tests and I forgot to add DNS redirection.
Now everything is working perfectly.
I hope this will help someone else!