I'm having problem with authorized requests ^[1].
Every requests with a valid auth token get:

error: {
    code: 4009
    message: "The 'auth' query parameter is not a valid auth token."
}

Renewing the token with /auth route does not fix the problem.

You can test it calling this:

http://www.stackprinter.com/export?format=HTML&service=stackapps&question=2164 ^[2]

or this:

http://www.stackprinter.com/topvoted?service=stackoverflow&tagged=python&page=1&pagesize=30 ^[3]

The returned headers are these:

* via - HTTP/1.1 GWA
* x-aspnet-version - 4.0.30319
* content-type - application/json; charset=utf-8
* x-google-cache-control - remote-fetch
* x-ratelimit-current - 0  <====== that was fixed long time ago
* cache-control - private
* date - Sat, 05 Mar 2011 08:30:52 GMT
* x-aspnetmvc-version - 3.0
* x-ratelimit-max - 0

EDIT:
still choking on several endpoints :(