[ubuntu] Why Ubuntu One is not sharing?

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http://ubuntuforums.org – I'm trying to share a folder on Ubuntu One, but I'm facing problems with it. I am trying to share a folder via web control panel (one.ubuntu.com), after giving the mail address of the other account (with which I want to share), it's showing that"Shared with ...@gmail.com to view/change files on Jan-08-2013 (waiting to be accepted)". Problem is that other account is not getting any notification or anything to accept that folder. More precisely, he is not getting any sign of new folder which wants to share with his accoun (Hardware)