我正在使用Nginx在Aeilla Ubuntu 14.04 VPS上安装Aegir，其次是： http://community.aegirproject.org/content/installing/manual/nginx-mariadb-php-fpm-single-server-installation
最后，在Aegir安装期间，我收到以下错误：
Could not rsync from '/var/aegir/config/server_master/nginx/subdir.d' to 'aegir@ nginx.drophost.eu:/' [error]
/var/aegir/config/server_master/nginx/subdir.d could not be synced to remote server nginx.drophost.eu. Changes might not be available[error]
until this has been done. (error: ssh: Could not resolve hostname nginx.drophost.eu: Name or service not known
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(226) [sender=3.1.0])
服务器域是nginx.drophost.eu，它正确解析为服务器IP，那有什么不对？