How to solve this problem--OAuth2::HTTPError: Received HTTP 400 during request problem with facebook_oauth in production server in Ruby on Rails??

Question

I am getting this exception with facebook_oauth 0.2.0 in production server -----------

OAuth2::HTTPError: Received HTTP 400 during request.>
Received HTTP 400 during request.
/usr/local/ruby-enterprise/lib/ruby/gems/1.8/gems/oauth2-0.1.0/lib/oauth2/client.rb:80:in `request'
/usr/local/ruby-enterprise/lib/ruby/gems/1.8/gems/oauth2-0.1.0/lib/oauth2/strategy/web_server.rb:15:in `get_access_token'

=> when executing this line of ruby code, access_token = @client.authorize(:code => params[:code])

But the same code working in the local server. I stumbled last two days about this issue. Anyone please help me??