We're sorry, but something went wrong. (Rails, Nginx, Puma, Postgres, Capistrano)

So I have been trying to deploy my rails app with no luck. There is no problem when I run:

cap production deploy

but when I open my server ip, the only thing I see is:

We're sorry, but something went wrong.

If you are the application owner check the logs for more information.

And I have checked the production.log the output is:

railties (4.2.4) lib/rails/engine.rb:518:incall' railties (4.2.4) lib/rails/application.rb:165:in call'
puma (2.14.0) lib/puma/configuration.rb:78:incall' puma (2.14.0) lib/puma/server.rb:541:in handle_request'
puma (2.14.0) lib/puma/server.rb:388:inprocess_client' puma (2.14.0) lib/puma/server.rb:270:in block in run'
puma (2.14.0) lib/puma/thread_pool.rb:106:incall' puma (2.14.0) lib/puma/thread_pool.rb:106:in block in spawn_thread'

How do I fix this? What could be the problem, any ideas?