Running sinatra program [Kibana] behind nginx reverse proxy in web directory

I'm trying to get Kibana to run behind nginx within a specific web directory. Or, put another way, I'm trying to have nginx reverse proxy http://example.com/kibana to http://localhost:5601/, which is where the Kibana sinatra app is running.

I've started Kibana with an init script, and if I curl the localhost url from the server, I get the expected response. However, navigating to http://example.com/kibana/ gives me the message of Sinatra doesn’t know this ditty. and a suggestion that /kibana/ should do something. Presumably, this is a routing issue.

My nginx config is simply this:

server {                                                                                                                                                       
    listen   80; ## listen for ipv4; this line is default and implied                                                                                          
    listen   [::]:80 default ipv6only=on; ## listen for ipv6                                                                                                   

    root /var/www;                                                                                                                                             
    index index.html index.htm;                                                                                                                                

    # Make site accessible from http://localhost/                                                                                                              
    server_name _;                                                                                                                                             

    location / {                                                                                                                                               
        # First attempt to serve request as file, then                                                                                                         
        # as directory, then fall back to index.html                                                                                                           
        try_files $uri $uri/ /index.html;                                                                                                                      
        # Uncomment to enable naxsi on this location                                                                                                           
        # include /etc/nginx/naxsi.rules                                                                                                                       
    }                                                                                                                                                          
    location /kibana/ {                                                                                                                                     
        proxy_pass  http://localhost:5601;                                                                                                                     
        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;                                                                  
        proxy_redirect off;                                                                                                                                    
        proxy_buffering off;                                                                                                                                   
        proxy_set_header        Host            $host;                                                                                                         
        proxy_set_header        X-Real-IP       $remote_addr;                                                                                                  
        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;                                                                                    
    }                                                                                                                                                          
}                           

I have one modification on the previous answer.

proxy_pass      http://127.0.0.1:5601;

Replace by

proxy_pass      http://127.0.0.1:5601/;