自从我升级到 18.04 以来，我就遇到了这个问题。我无法连接到我的大学网络。其他 Ubuntu 用户可以。我可以连接到我的家庭网络或热点网络。我尝试使用 wicd 而不是网络管理器，但没有成功。
我见过类似的帖子，但都没有帮助！
提前致谢。
EDIT1：今天我尝试连接到大学网络时添加了 journalctl $(type -p NetworkManager) 的输出。（Pardis Olum 是我尝试连接的网络。）我的大学是德黑兰大学，连接前不需要任何类型的配置。
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.8792] NetworkManager (version 1.10.6) is starting... (for the first time)
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.8792] Read config: /etc/NetworkManager/NetworkManager.conf (lib: 10-dns-resolved.conf, 20-connectivity-ubuntu.conf, no-mac-addr-chang
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9132] manager[0x55a15b04b060]: monitoring kernel firmware directory '/lib/firmware'.
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9132] monitoring ifupdown state file '/run/network/ifstate'.
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9230] hostname: hostname: using hostnamed
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9231] hostname: hostname changed from (none) to "arian-Lenovo"
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9234] dns-mgr[0x55a15b067140]: init: dns=systemd-resolved, rc-manager=symlink, plugin=systemd-resolved
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9245] rfkill2: found WiFi radio killswitch (at /sys/devices/pci0000:00/0000:00:1c.3/0000:02:00.0/ieee80211/phy0/rfkill2) (driver rtl8
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9247] rfkill0: found WiFi radio killswitch (at /sys/devices/pci0000:00/0000:00:1f.0/PNP0C09:00/VPC2004:00/rfkill/rfkill0) (platform d
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9267] manager[0x55a15b04b060]: rfkill: WiFi hardware radio set enabled
Jul 22 10:18:14 arian-Lenovo NetworkManager[1229]: <info> [1532238494.9268] manager[0x55a15b04b060]: rfkill: WWAN hardware radio set enabled
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1054] init!
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1056] interface-parser: parsing file /etc/network/interfaces
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1056] interface-parser: finished parsing file /etc/network/interfaces
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1056] management mode: unmanaged
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1060] devices added (path: /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/enp1s0, iface: enp1s0)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1060] device added (path: /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/enp1s0, iface: enp1s0): no ifupdown configuration fou
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1060] devices added (path: /sys/devices/pci0000:00/0000:00:1c.3/0000:02:00.0/net/wlp2s0, iface: wlp2s0)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1060] device added (path: /sys/devices/pci0000:00/0000:00:1c.3/0000:02:00.0/net/wlp2s0, iface: wlp2s0): no ifupdown configuration fou
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1061] devices added (path: /sys/devices/virtual/net/lo, iface: lo)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1061] device added (path: /sys/devices/virtual/net/lo, iface: lo): no ifupdown configuration found.
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1061] end _init.
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1061] settings: loaded plugin ifupdown: (C) 2008 Canonical Ltd. To report bugs please use the NetworkManager mailing list. (/usr/lib
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1061] settings: loaded plugin keyfile: (c) 2007 - 2016 Red Hat, Inc. To report bugs please use the NetworkManager mailing list.
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1061] (1527275712) ... get_connections.
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1061] (1527275712) ... get_connections (managed=false): return empty list.
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1178] keyfile: new connection /etc/NetworkManager/system-connections/arian (37a91a54-74b3-4e9b-a729-461ba0538fca,"arian")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1276] keyfile: new connection /etc/NetworkManager/system-connections/Library (abd4fff7-9dba-483c-bacc-364fecde524c,"Library")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1427] keyfile: new connection /etc/NetworkManager/system-connections/Etelsep (77fd0dcf-7cff-47be-b68e-0cfae2011ae1,"Etelsep")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1520] keyfile: new connection /etc/NetworkManager/system-connections/Pardise olum (19e734f6-05a4-4312-8a03-d0ad765edb8b,"Pardise olum
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1615] keyfile: new connection /etc/NetworkManager/system-connections/AndroidAP (961e96e3-28b5-49f6-8786-7fc7a77e4f53,"AndroidAP")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1708] keyfile: new connection /etc/NetworkManager/system-connections/Arianhf (61623a21-1411-4e06-9544-3734bc3d2014,"Arianhf")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1801] keyfile: new connection /etc/NetworkManager/system-connections/Barbod (4d3f3f46-e3cb-4049-80f3-467540693e1a,"Barbod")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1896] keyfile: new connection /etc/NetworkManager/system-connections/IBB (5c16f134-563a-4a60-a013-fa4323862551,"IBB")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.1989] keyfile: new connection /etc/NetworkManager/system-connections/MobinNet3869 (381b1ddf-c2c4-4f7c-8c07-1ab255f71abf,"MobinNet3869
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.2098] keyfile: new connection /etc/NetworkManager/system-connections/MobinNet4305 (02c6b593-dd7f-4abd-bf2e-15c7d6b505df,"MobinNet4305
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.2198] keyfile: new connection /etc/NetworkManager/system-connections/BgwW-YXJpYW4uaGVkYXlhdGlmYXI (908cb40e-9e5c-4cd7-b118-4d07ef4021
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.2295] keyfile: new connection /etc/NetworkManager/system-connections/mTnet (d76e9781-b0a4-462b-9ad6-562338cb1e90,"mTnet")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.2392] keyfile: new connection /etc/NetworkManager/system-connections/lgk10 (f60cdae1-da52-4c01-a2d6-a160ade8146f,"lgk10")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3558] get unmanaged devices count: 0
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3559] manager: rfkill: WiFi disabled by radio killswitch; enabled by state file
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3559] manager: rfkill: WWAN enabled by radio killswitch; enabled by state file
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3559] manager: Networking is enabled by state file
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3561] dhcp-init: Using DHCP client 'dhclient'
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3561] Loaded device plugin: NMBondDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3562] Loaded device plugin: NMBridgeDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3562] Loaded device plugin: NMDummyDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3562] Loaded device plugin: NMEthernetDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3562] Loaded device plugin: NMInfinibandDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3563] Loaded device plugin: NMIPTunnelDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3563] Loaded device plugin: NMMacsecDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3563] Loaded device plugin: NMMacvlanDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3563] Loaded device plugin: NMPppDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3563] Loaded device plugin: NMTunDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3563] Loaded device plugin: NMVethDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3564] Loaded device plugin: NMVlanDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3564] Loaded device plugin: NMVxlanDeviceFactory (internal)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.3572] Loaded device plugin: NMWwanFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/libnm-device-plugin-wwan.so)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5239] Loaded device plugin: NMTeamFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/libnm-device-plugin-team.so)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5868] Loaded device plugin: NMBluezManager (/usr/lib/x86_64-linux-gnu/NetworkManager/libnm-device-plugin-bluetooth.so)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5871] Loaded device plugin: NMWifiFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/libnm-device-plugin-wifi.so)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5874] Loaded device plugin: NMAtmManager (/usr/lib/x86_64-linux-gnu/NetworkManager/libnm-device-plugin-adsl.so)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5882] device (lo): carrier: link connected
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5888] manager: (lo): new Generic device (/org/freedesktop/NetworkManager/Devices/1)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5899] manager: (enp1s0): new Ethernet device (/org/freedesktop/NetworkManager/Devices/2)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5910] keyfile: add connection in-memory (076c6cef-aa47-3aa3-9870-5f84ef151d50,"Wired connection 1")
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5915] settings: (enp1s0): created default wired connection 'Wired connection 1'
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5925] device (enp1s0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.5997] wifi-nl80211: (wlp2s0): using nl80211 for WiFi device control
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.6000] device (wlp2s0): driver supports Access Point (AP) mode
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.6009] manager: (wlp2s0): new 802.11 WiFi device (/org/freedesktop/NetworkManager/Devices/3)
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.6018] device (wlp2s0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Jul 22 10:18:15 arian-Lenovo NetworkManager[1229]: <info> [1532238495.6037] manager: rfkill: WiFi now enabled by radio killswitch
Jul 22 10:18:16 arian-Lenovo NetworkManager[1229]: <info> [1532238496.3745] modem-manager: ModemManager available
Jul 22 10:18:16 arian-Lenovo NetworkManager[1229]: <info> [1532238496.3752] bluez: use BlueZ version 5
Jul 22 10:18:16 arian-Lenovo NetworkManager[1229]: <info> [1532238496.3763] supplicant: wpa_supplicant running
Jul 22 10:18:16 arian-Lenovo NetworkManager[1229]: <info> [1532238496.3763] device (wlp2s0): supplicant interface state: init -> starting
Jul 22 10:18:16 arian-Lenovo NetworkManager[1229]: <info> [1532238496.3784] bluez5: NAP: added interface 00:71:CC:7D:96:2A
Jul 22 10:18:16 arian-Lenovo NetworkManager[1229]: <info> [1532238496.4293] device (wlp2s0): supplicant interface state: starting -> ready
Jul 22 10:18:16 arian-Lenovo NetworkManager[1229]: <info> [1532238496.4294] device (wlp2s0): state change: unavailable -> disconnected (reason 'supplicant-available', sys-iface-state: 'managed')
Jul 22 10:18:21 arian-Lenovo NetworkManager[1229]: <info> [1532238501.5936] manager: startup complete
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7004] device (wlp2s0): Activation: starting connection 'Pardise olum' (19e734f6-05a4-4312-8a03-d0ad765edb8b)
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7006] audit: op="connection-activate" uuid="19e734f6-05a4-4312-8a03-d0ad765edb8b" name="Pardise olum" pid=2566 uid=1000 result="succe
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7009] device (wlp2s0): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed')
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7011] manager: NetworkManager state is now CONNECTING
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7017] device (wlp2s0): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7020] device (wlp2s0): Activation: (wifi) connection 'Pardise olum' requires no security. No secrets needed.
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7020] Config: added 'ssid' value 'Pardise olum'
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7021] Config: added 'scan_ssid' value '1'
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7021] Config: added 'bgscan' value 'simple:30:-80:86400'
Jul 22 10:26:24 arian-Lenovo NetworkManager[1229]: <info> [1532238984.7021] Config: added 'key_mgmt' value 'NONE'
Jul 22 10:26:25 arian-Lenovo NetworkManager[1229]: <info> [1532238985.2251] device (wlp2s0): supplicant interface state: ready -> authenticating
Jul 22 10:26:25 arian-Lenovo NetworkManager[1229]: <info> [1532238985.2313] device (wlp2s0): supplicant interface state: authenticating -> associating
Jul 22 10:26:25 arian-Lenovo NetworkManager[1229]: <info> [1532238985.2428] device (wlp2s0): supplicant interface state: associating -> completed
Jul 22 10:26:25 arian-Lenovo NetworkManager[1229]: <info> [1532238985.2428] device (wlp2s0): Activation: (wifi) Stage 2 of 5 (Device Configure) successful. Connected to wireless network 'Pardise olum'.
Jul 22 10:26:25 arian-Lenovo NetworkManager[1229]: <info> [1532238985.2443] device (wlp2s0): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed')
Jul 22 10:26:25 arian-Lenovo NetworkManager[1229]: <info> [1532238985.2520] dhcp4 (wlp2s0): activation: beginning transaction (timeout in 45 seconds)
Jul 22 10:26:25 arian-Lenovo NetworkManager[1229]: <info> [1532238985.2535] dhcp4 (wlp2s0): dhclient started with pid 8116
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <warn> [1532239031.0013] dhcp4 (wlp2s0): request timed out
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <info> [1532239031.0013] dhcp4 (wlp2s0): state changed unknown -> timeout
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <info> [1532239031.0176] dhcp4 (wlp2s0): canceled DHCP transaction, DHCP client pid 8116
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <info> [1532239031.0176] dhcp4 (wlp2s0): state changed timeout -> done
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <info> [1532239031.0179] device (wlp2s0): state change: ip-config -> failed (reason 'ip-config-unavailable', sys-iface-state: 'managed')
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <info> [1532239031.0181] manager: NetworkManager state is now DISCONNECTED
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <warn> [1532239031.0185] device (wlp2s0): Activation: failed for connection 'Pardise olum'
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <info> [1532239031.0194] device (wlp2s0): state change: failed -> disconnected (reason 'none', sys-iface-state: 'managed')
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <warn> [1532239031.0419] sup-iface[0x55a15b01fa40,wlp2s0]: connection disconnected (reason -3)
Jul 22 10:27:11 arian-Lenovo NetworkManager[1229]: <info> [1532239031.0495] device (wlp2s0): supplicant interface state: completed -> disconnected
Jul 22 10:27:12 arian-Lenovo NetworkManager[1229]: <info> [1532239032.6283] device (wlp2s0): supplicant interface state: disconnected -> disabled
Jul 22 10:27:13 arian-Lenovo NetworkManager[1229]: <info> [1532239033.2465] supplicant: wpa_supplicant stopped
Jul 22 10:27:13 arian-Lenovo NetworkManager[1229]: <info> [1532239033.2466] device (wlp2s0): supplicant interface state: disabled -> down
Jul 22 10:27:13 arian-Lenovo NetworkManager[1229]: <info> [1532239033.2470] device (wlp2s0): state change: disconnected -> unavailable (reason 'supplicant-failed', sys-iface-state: 'managed')
Jul 22 10:27:23 arian-Lenovo NetworkManager[1229]: <info> [1532239043.0048] supplicant: wpa_supplicant die count reset