我能够连接到不需要密码的 wifi 网络。但是当我尝试连接到需要密码的网络时，没有询问密码，网络管理器只是尝试连接，当然它失败了。
这是来自 /var/log/syslog 的日志：
NetworkManager[936]: <info> [1495625898.1943] device (wlp2s0): Activation: starting connection 'true_home2G_b68' (ea2f25dd-98bd-4e72-b660-5ac56c683519)
NetworkManager[936]: <info> [1495625898.1944] audit: op="connection-activate" uuid="ea2f25dd-98bd-4e72-b660-5ac56c683519" name="true_home2G_b68" pid=2168 uid=1000 result="success"
NetworkManager[936]: <info> [1495625898.1945] device (wlp2s0): state change: disconnected -> prepare (reason 'none') [30 40 0]
NetworkManager[936]: <info> [1495625898.1946] manager: NetworkManager state is now CONNECTING
NetworkManager[936]: <info> [1495625898.1951] device (wlp2s0): state change: prepare -> config (reason 'none') [40 50 0]
NetworkManager[936]: <info> [1495625898.1953] device (wlp2s0): Activation: (wifi) access point 'true_home2G_b68' has security, but secrets are …