Error

          @API_KEY = 'asdfghj'
          @API_SECRET = 'asdfghjklfrgh'
          
          def get_http(url, body=nil)
            @nonce = (Time.now.to_f * 1e6).to_i
            @message = @nonce.to_s + url + body.to_s
            @signature = OpenSSL::HMAC.hexdigest(OpenSSL::Digest::Digest.new('sha256'), @API_SECRET, @message)
            @headers = {"ACCESS_KEY" => @API_KEY, "ACCESS_SIGNATURE" => @signature, "ACCESS_NONCE" => @nonce}
            begin
              if body.nil?
                RestClient.get(url, @headers)
              else
                RestClient.post(url, body, @headers)
              end
            rescue => e
              puts e
              e.response
            end
          end

          button = { 
            :name => 'meep', 
            :type => 'buy_now', 
            :description => "Coins you're willing to sell with meep.", 
            :style => 'none', 
            :custom => @user.token, 
            :custom_secure => true, 
            :variable_price => true, 
            :price_string => "0.400", 
            :price_currency_iso => 'BTC', 
            :text => "Send to us",
            :choose_price => true,
            :auto_redirect => true,
            :callback_url => "#{root_url}?ssecret=85HgugcNRqg9"
          }
          response =  get_http('https://coinbase.com/api/v1/buttons', button)

ERROR: ACCESS_SIGNATURE does not validate