Evolution can't load Google calendar anymore

[Gorgonilla]

I have a Google calendar entry in my calendars. When I click it I get the following error:

Error loading calendar
Cannot open calendar: unexpected HTTP status code 3 returned

It was working until July then it stopped working.
I've tried removing and recreating it (and in the creation form it correctly retrieves the calendar list) but when then I click on it I still get the above error.

I'm using Ubuntu Natty 11.04 64bit (2.6.38-11-generic kernel) and Evolution version is 2.32.2-0ubuntu7

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: evolution 2.32.2-0ubuntu7
ProcVersionSignature: Ubuntu 2.6.38-11.48-generic 2.6.38.8
Uname: Linux 2.6.38-11-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Mon Aug 22 10:43:49 2011
ExecutablePath: /usr/bin/evolution
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: evolution
UpgradeStatus: No upgrade log present (probably fresh install)

[Gorgonilla (lviggiani)]

I have additional information on this:

The problem only occurs to me if I set a proxy for internet connection. If I disable the proxy and connect to internet directly, I can load my google calendar without any problem as before.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.