Comment 9 for bug 1321650

All this means is that the authentication was rejected by the AP.

What I see even more interesting is this:

May 21 08:05:08 ubuntu-phablet kernel: [ 332.441294] wlan: [1284:E :SME] csrNeighborRoamPrepareScanProfileFilter: 1197: Filtering for SSID darline from scan results,length of SSID = 7
May 21 08:05:08 ubuntu-phablet kernel: [ 332.442270] wlan: [1284:E :SME] csrNeighborRoamProcessScanComplete: 1867: No candidate found after scanning in state 3..

Are there any updates that were done on this device? What is the current image version, and when did this trouble start?

The failure code 13 that we see in the errors means:
"Responding STA does not support the specified authentication algorithm"

This makes it even more important to know when this started, so that we can find out what changed.

One thing to try would be to connect to the device via ADB and edit the file:
/etc/NetworkManager/system-connections/darline

Remove the line "wep-tx-keyidx=0" if it's there, and add a line:
wep-key-type=2

In the same section, if it isn't already in place. All this should be under the 802-11-wireless-security section.

I've created a file locally to test (attached). Do note that you will need to do a few steps to transfer a file like that on your device (and you will need to set the right passphrase in wep-key0) :

adb push darline /etc/NetworkManager/system-connections/darline
adb shell chmod 600 /etc/NetworkManager/system-connections/darline
adb shell touch /etc/NetworkManager/system-connections/darline

You may also need to reboot the phone to be sure the new file is used.