Not sure if this is a user or an API problem, but I keep getting HTTP 406 Not Acceptable when making API calls (for example http://api.stackoverflow.com/0.8/stats) from either IE 8 or Chrome 6.
Here are the headers for the two requests.
IE 8:
GET /0.8/stats HTTP/1.1
Accept: application/x-ms-application, image/jpeg, application/xaml+xml, image/gif, image/pjpeg, application/x-ms-xbap, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Accept-Language: en-US
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; MS-RTC LM 8; Zune 4.0; .NET4.0C; .NET4.0E; InfoPath.3)
Accept-Encoding: gzip, deflate
Proxy-Connection: Keep-Alive
Host: api.stackoverflow.com
Chrome 6:
GET /0.8/stats HTTP/1.1
Host: api.stackoverflow.com
Proxy-Connection: keep-alive
Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.9 (KHTML, like Gecko) Chrome/6.0.401.1 Safari/533.9
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Update: Awesome news! After the latest changes by @Kevin the API works as expected behind the corpnet proxy for me.