wireless - repeated password dialog for laptop wifi connection

I'm having the classic problem when trying to connect my laptop to wifi - repeated password dialogs, even though the credentials have been entered. I'm using the standard network manager.

Machine specs are -

• Xubuntu 14.04LTS


• Lenovo ThinkPad T430


• Intel Centrino Wireless N 6205

Insecure networks can be connected to just fine...

I tested out debian xfce on this machine previously, and this page got my wifi working. I hesitantly tried it in xubuntu to no avail - after installing the iwlwifi drivers manually (as described here) as they are not in the ubuntu repos.

When running network manager from terminal, here is the output when I try and connect -

NetworkManager[2816]:  Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
NetworkManager[2816]:  Config: set interface ap_scan to 1

NetworkManager[2816]:  (wlan0): supplicant interface state: inactive -> scanning
NetworkManager[2816]:  (wlan0): supplicant interface state: scanning -> authenticating
NetworkManager[2816]:  (wlan0): supplicant interface state: authenticating -> associating
NetworkManager[2816]:  (wlan0): supplicant interface state: associating -> disconnected

It loops around between those last two indefinitely...

$ rfkill list all
0: tpacpi_bluetooth_sw: Bluetooth
    Soft blocked: no

    Hard blocked: no
1: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
5: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no

    $ lspci | grep Network
    00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 04)
    03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] (rev 34)

$ dmesg | grep iwl
[    9.316455] iwlwifi 0000:03:00.0: can't disable ASPM; OS doesn't have ASPM control
[    9.317203] iwlwifi 0000:03:00.0: irq 44 for MSI/MSI-X
[    9.764860] iwlwifi 0000:03:00.0: loaded firmware version 18.168.6.1 op_mode iwldvm
[    9.778358] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUG disabled
[    9.778361] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUGFS enabled

[    9.778362] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled
[    9.778364] iwlwifi 0000:03:00.0: Detected Intel(R) Centrino(R) Advanced-N 6205 AGN, REV=0xB0
[    9.778516] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[    9.800853] ieee80211 phy0: Selected rate control algorithm 'iwl-agn-rs'
[   40.579731] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[   40.586571] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[   40.849802] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[   40.856653] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[  982.322399] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[  982.329333] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0

[ 1010.374609] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[ 1010.383406] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[ 1736.676404] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[ 1736.683251] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[ 1832.021397] Modules linked in: snd_seq_dummy bnep rfcomm uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core btusb bluetooth v4l2_common videodev media 6lowpan_iphc arc4 iwldvm mac80211 snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel snd_hda_intel aes_x86_64 snd_hda_controller lrw snd_hda_codec gf128mul snd_hwdep glue_helper ablk_helper cryptd snd_pcm thinkpad_acpi nvram snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer joydev serio_raw iwlwifi cfg80211 parport_pc mei_me ppdev snd lpc_ich mei wmi lp parport soundcore i915 drm_kms_helper video drm i2c_algo_bit mac_hid psmouse e1000e sdhci_pci ptp sdhci pps_core ahci libahci
[ 1835.176504] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[ 1835.183655] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[ 2094.504128] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[ 2094.511431] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0

$ uname -a
Linux t430 3.16.0-28-lowlatency #38-Ubuntu SMP PREEMPT Sat Dec 13 16:41:52 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

Messing about with the router config isn't really a good option, as many devices use this network.