I suggest you try setting a larger buffer size with
large_client_header_buffers
<http://nginx.org/en/docs/http/ngx_http_core_module.html#large_client_header_buffers>.
The docs are really clear about the fact a request line cannot exceed the
size of a single buffer (*not* the number * size value).

By changing from the GET to the POST method, are you sure you did not
change anything else about the headers sent? Trying to make your tests
(replaying both the KO & OK requests) with a command-line client displaying
all those headers to you might prove useful.
---
*B. R.*

On Wed, Nov 11, 2015 at 6:37 PM, Spencer Fu <lists@ruby-forum.com> wrote:

> I changed the request from a get to a post in order to get it working
> for my site.
>
> --
> Posted via http://www.ruby-forum.com/.
>
> _______________________________________________
> nginx mailing list
> nginx@nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx
>
_______________________________________________
nginx mailing list
nginx@nginx.org
http://mailman.nginx.org/mailman/listinfo/nginx