Exactly how does it redirect? Does it send a page with a redirect META tag or does it send a 3XX HTTP status response?
The response I get is coded 502 - Bad Gateway, which is defined as:
Code:
The server, while acting as a gateway or proxy, received an invalid response
from the upstream server it accessed in attempting to fulfill the request.
So however the redirect is being done, the nginx server doesn't like it. Hard to say without seeing the relevant code.