我尝试从Redmine上的Gmail帐户接收收到的邮件，但我的组织使用经过身份验证的代理，我收到此错误：
$ sudo rake -f /app/redmine-2.4.5/Rakefile redmine:email:receive_imap RAILS_ENV="production" host=imap.gmail.com port=993 ssl=1 username=foo@gmail.com password=foopassword project=myotragus unknown_user=accept folder=INBOX move_on_success=redmine-processed move_on_failure=redmine-error allow_override=project unknown_user=accept no_permission_check=1 --trace
** Invoke redmine:email:receive_imap (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute redmine:email:receive_imap
rake aborted!
Network is unreachable - connect(2)
/usr/lib/ruby/1.9.1/net/imap.rb:1034:in `initialize'
/usr/lib/ruby/1.9.1/net/imap.rb:1034:in `open'
/usr/lib/ruby/1.9.1/net/imap.rb:1034:in `initialize'
/app/redmine-2.4.5/lib/redmine/imap.rb:29:in `new'
/app/redmine-2.4.5/lib/redmine/imap.rb:29:in `check'
/app/redmine-2.4.5/lib/tasks/email.rake:125:in `block (3 levels) in <top (required)>'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/task.rb:236:in `call'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/task.rb:236:in `block in execute'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/task.rb:231:in `each'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/task.rb:231:in `execute'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/task.rb:175:in `block in invoke_with_call_chain'
/usr/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/task.rb:168:in `invoke_with_call_chain'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/task.rb:161:in `invoke'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:149:in `invoke_task'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:106:in `each'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:106:in `block in top_level'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:115:in `run_with_threads'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:100:in `top_level'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:78:in `block in run'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:165:in `standard_exception_handling'
/var/lib/gems/1.9.1/gems/rake-10.1.1/lib/rake/application.rb:75:in `run'
/var/lib/gems/1.9.1/gems/rake-10.1.1/bin/rake:33:in `<top (required)>'
/usr/local/bin/rake:23:in `load'
/usr/local/bin/rake:23:in `<main>'
Tasks: TOP => redmine:email:receive_imap
有没有办法在代理后面的Redmine中连接Gmail帐户？ 我在Ubuntu 14.10上使用了Redmine-2.4.5，并且我已经定义了http_proxy env var。