Thank you for the bug report. The error message was incorrect. You
should receive a 406 error code with the message "Server response is Not
Acceptable".
The error is caused by the web server disconnecting before sending a
valid HTTP response. POE::Component::Client::HTTP builds a default 406
Not Acceptable response to notify your application what happened.
The fix has been committed as revision 356, and it will appear in the
next release.