[Evolution] Google calendars stopped working in Evolution

[Bjørn-Helge Mevik <b h mevik usit uio no>]

I have Evolution 2.28.3 (the version that comes with RHEL 6), and
earlier this year, I added a couple of Google calendars to it (with
New=>Calendar=>Type: Google).  This worked fine.

Very recently (about two weeks ago), this stopped working.  Evolution
will not show the Google calendars anymore.  If I click on one of them,
the status bar at the bottom will say

  Opening caldav://myusername%40gmail com www google com/calendar/dav/myusername gmail com/events (...)

for a very long time, but nothing will show up.  Eventually, the
checkbox for showing the calendar will be deselected.

I am pretty sure I have the right password for the Google account,
because if I right-click the calender, select Properties, Retrieve list,
and give the password, then I will get the list of available calendars
for the account.

Is this a known problem, or have I done something wrong?

-- 
Regards,
Bjørn-Helge Mevik, dr. scient,
Department for Research Computing, University of Oslo