Can not authenticate in Ubuntu One behind a proxy
After installing it at home without any problem, I'm trying to install Ubuntu One at work (Ubuntu 12.04, must use proxy). Apparently it can not connect to the server: I can't sign in of course, can't use the "forgotten password" form either (address not recognized), and if I open the dialog to create an account I get a message "There was a problem downloading the captcha, reloading...".
I tried installing ubuntuone-client-proxy, following
and resinstalling the certificates, following https://one.ubuntu.com/help/faq/why-...n-windows-225/ (though actually this does not apply to my case)
... without any success.
Does someone has any idea what I am doing wrong? What I could try?
Remark: I had previously posted this question on askubuntu but didn't get any answer:
I also saw that similar questions were asked here with limited success: