Codiginter 3 : 404 for all pages except assest

I am trying to deploy my Codeigniter 3 HMVC website in nginx (AWS). I have tried all the solutions I found in SO but none of them worked. It is been 6 hours now. Please someone help m e out here.

I have installed nginx and tested a "Hello World" in a PHP file and it works fine.

(All the static files in assets/ folder are served in the browser. Only the routing seems to cause the issue for other urls)

This is the configs in my /etc/nginx/sites-enabled/blahblah.lk

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    root /var/www/blah/public/;
    index index.php index.html index.htm;

    # Make site accessible from http://localhost/
    server_name blahblah.lk;

    location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to displaying a 404.
        try_files $uri $uri/ /index.php;
    }

        location ~* ~/(assets|files|robots\.txt){}

        # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests
    #location /RequestDenied {
    #   proxy_pass http://127.0.0.1:8080;
    #}

    #error_page 404 /404.html;

    # redirect server error pages to the static page /50x.html
    #
    #error_page 500 502 503 504 /50x.html;
    #location = /50x.html {
    #   root /usr/share/nginx/html;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
    #   # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
    #
    #   # With php5-cgi alone:
            #fastcgi_pass 127.0.0.1:9000;
        # With php5-fpm:
        fastcgi_pass unix:/var/run/php5-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
    }

If nginx is running properly, it might be a codeigniter setup issue.

Check the rewrite rules and make sure your controllers have uppercase-first filenames, while the controller subfolders are all-lowercase. That kept me from going for hours.