Some additional problem/debugging data. I disconnected via NM. I removed relevant driver modules. # lsmod |grep iwlwifi iwlwifi 172032 1 iwlmvm cfg80211 466944 3 iwlwifi,mac80211,iwlmvm # modprobe -r iwlwifi modprobe: FATAL: Module iwlwifi is in use. # modprobe -r iwlmvm # lsmod |grep iwlwifi # I added those modules back. # modprobe iwlmvm # lsmod |grep iwlwifi iwlwifi 172032 1 iwlmvm cfg80211 466944 3 iwlwifi,mac80211,iwlmvm I tried multiple times to reestablish NM connection, but without success (in my original problem report I was refused the first time only, the second attempt was always successful). There were the messages: Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): Activation: starting connection 'AP-jb' (1c51ed53-1e7d-4274-bfe7-2afc8034014a) Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): device state change: disconnected -> prepare (reason 'none') [30 40 0] Oct 15 11:16:09 myhost NetworkManager[378]: NetworkManager state is now CONNECTING Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): device state change: prepare -> config (reason 'none') [40 50 0] Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): Activation: (wifi) access point 'AP-jb' has security, but secrets are required. Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): device state change: config -> need-auth (reason 'none') [50 60 0] Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): device state change: need-auth -> prepare (reason 'none') [60 40 0] Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): device state change: prepare -> config (reason 'none') [40 50 0] Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): Activation: (wifi) connection 'AP-jb' has security, and secrets exist. No new secrets needed. Oct 15 11:16:09 myhost NetworkManager[378]: Config: added 'ssid' value 'AP-jb' Oct 15 11:16:09 myhost NetworkManager[378]: Config: added 'scan_ssid' value '1' Oct 15 11:16:09 myhost NetworkManager[378]: Config: added 'key_mgmt' value 'WPA-PSK' Oct 15 11:16:09 myhost NetworkManager[378]: Config: added 'psk' value '' Oct 15 11:16:09 myhost NetworkManager[378]: Config: set interface ap_scan to 1 Oct 15 11:16:09 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: disconnected -> scanning Oct 15 11:16:19 myhost kernel: wlp4s0: authenticate with f8:d1:11:99:18:6c Oct 15 11:16:19 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: scanning -> authenticating Oct 15 11:16:19 myhost kernel: wlp4s0: send auth to f8:d1:11:99:18:6c (try 1/3) Oct 15 11:16:19 myhost kernel: wlp4s0: authenticated Oct 15 11:16:19 myhost kernel: iwlwifi 0000:04:00.0: No association and the time event is over already... Oct 15 11:16:19 myhost kernel: wlp4s0: Connection to AP f8:d1:11:99:18:6c lost Oct 15 11:16:24 myhost kernel: wlp4s0: aborting authentication with f8:d1:11:99:18:6c by local choice (Reason: 3=DEAUTH_LEAVING) Oct 15 11:16:24 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: authenticating -> disconnected Oct 15 11:16:34 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: disconnected -> scanning Oct 15 11:16:34 myhost NetworkManager[378]: (wlp4s0): Activation: (wifi) association took too long, failing activation Oct 15 11:16:34 myhost NetworkManager[378]: (wlp4s0): device state change: config -> failed (reason 'ssid-not-found') [50 120 53] Oct 15 11:16:34 myhost NetworkManager[378]: NetworkManager state is now DISCONNECTED Oct 15 11:16:34 myhost NetworkManager[378]: (wlp4s0): Activation: failed for connection 'AP-jb' Oct 15 11:16:34 myhost NetworkManager[378]: (wlp4s0): device state change: failed -> disconnected (reason 'none') [120 30 0] Oct 15 11:16:34 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: scanning -> disconnected Oct 15 11:16:34 myhost kernel: IPv6: ADDRCONF(NETDEV_UP): wlp4s0: link is not ready Oct 15 11:16:34 myhost NetworkManager[378]: Failed to GDBus.Error:fi.w1.wpa_supplicant1.NotConnected: This interface is not connected: disconnect. To restore WiFI I did the following steps. Right-click NM applet. Turned off Enable Wi-Fi. Oct 15 11:21:55 myhost NetworkManager[378]: WiFi hardware radio set disabled Oct 15 11:21:55 myhost NetworkManager[378]: (wlp4s0): device state change: disconnected -> unavailable (reason 'none') [30 20 0] Oct 15 11:21:55 myhost NetworkManager[378]: WiFi now disabled by radio killswitch Turned on Enable Wi-Fi. Oct 15 11:22:47 myhost NetworkManager[378]: WiFi hardware radio set enabled Oct 15 11:22:47 myhost kernel: iwlwifi 0000:04:00.0: L1 Enabled - LTR Enabled Oct 15 11:22:47 myhost kernel: iwlwifi 0000:04:00.0: L1 Enabled - LTR Enabled Oct 15 11:22:47 myhost kernel: iwlwifi 0000:04:00.0: L1 Enabled - LTR Enabled Oct 15 11:22:47 myhost kernel: iwlwifi 0000:04:00.0: L1 Enabled - LTR Enabled Oct 15 11:22:47 myhost NetworkManager[378]: WiFi now enabled by radio killswitch Oct 15 11:22:47 myhost kernel: IPv6: ADDRCONF(NETDEV_UP): wlp4s0: link is not ready Oct 15 11:22:47 myhost NetworkManager[378]: (wlp4s0) supports 5 scan SSIDs Oct 15 11:22:47 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: starting -> ready Oct 15 11:22:47 myhost NetworkManager[378]: (wlp4s0): device state change: unavailable -> disconnected (reason 'supplicant-available') [20 30 42] Oct 15 11:22:47 myhost kernel: IPv6: ADDRCONF(NETDEV_UP): wlp4s0: link is not ready Oct 15 11:22:57 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: ready -> inactive I tried to establish NM connection multiple times, without success. There were the messages: Oct 15 11:23:57 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: inactive -> scanning Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): Activation: starting connection 'AP-jb' (1c51ed53-1e7d-4274-bfe7-2afc8034014a) Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): device state change: disconnected -> prepare (reason 'none') [30 40 0] Oct 15 11:24:15 myhost NetworkManager[378]: NetworkManager state is now CONNECTING Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): device state change: prepare -> config (reason 'none') [40 50 0] Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): Activation: (wifi) access point 'AP-jb' has security, but secrets are required. Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): device state change: config -> need-auth (reason 'none') [50 60 0] Oct 15 11:24:15 myhost NetworkManager[378]: Failed to GDBus.Error:fi.w1.wpa_supplicant1.NotConnected: This interface is not connected: disconnect. Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): device state change: need-auth -> prepare (reason 'none') [60 40 0] Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): device state change: prepare -> config (reason 'none') [40 50 0] Oct 15 11:24:15 myhost NetworkManager[378]: (wlp4s0): Activation: (wifi) connection 'AP-jb' has security, and secrets exist. No new secrets needed. Oct 15 11:24:15 myhost NetworkManager[378]: Config: added 'ssid' value 'AP-jb' Oct 15 11:24:15 myhost NetworkManager[378]: Config: added 'scan_ssid' value '1' Oct 15 11:24:15 myhost NetworkManager[378]: Config: added 'key_mgmt' value 'WPA-PSK' Oct 15 11:24:15 myhost NetworkManager[378]: Config: added 'psk' value '' Oct 15 11:24:15 myhost NetworkManager[378]: Failed to GDBus.Error:fi.w1.wpa_supplicant1.NotConnected: This interface is not connected: disconnect. Oct 15 11:24:15 myhost NetworkManager[378]: Config: set interface ap_scan to 1 Oct 15 11:24:40 myhost NetworkManager[378]: (wlp4s0): Activation: (wifi) association took too long, failing activation Oct 15 11:24:40 myhost NetworkManager[378]: (wlp4s0): device state change: config -> failed (reason 'ssid-not-found') [50 120 53] Oct 15 11:24:40 myhost NetworkManager[378]: NetworkManager state is now DISCONNECTED Oct 15 11:24:40 myhost NetworkManager[378]: (wlp4s0): Activation: failed for connection 'AP-jb' Oct 15 11:24:40 myhost NetworkManager[378]: (wlp4s0): device state change: failed -> disconnected (reason 'none') [120 30 0] Oct 15 11:24:40 myhost kernel: IPv6: ADDRCONF(NETDEV_UP): wlp4s0: link is not ready Oct 15 11:24:40 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: scanning -> disconnected Oct 15 11:24:40 myhost NetworkManager[378]: Failed to GDBus.Error:fi.w1.wpa_supplicant1.NotConnected: This interface is not connected: disconnect. Oct 15 11:24:40 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: disconnected -> scanning Oct 15 11:24:50 myhost NetworkManager[378]: (wlp4s0): supplicant interface state: scanning -> disconnected I logged out from DE to tty, and back again (restarted nm-applet). $ ps -ef | egrep -i '(nm|net)' root 378 1 0 Oct14 ? 00:00:16 /usr/bin/NetworkManager --no-daemon jb 534 1 0 Oct14 tty1 00:00:07 nm-applet I could not establish NM connection. I reset AP (wireless router). I could not establish NM connection. Somehow unloading and reloading those wireless driver modules broke the camel. But should it be so ? I had to reboot my laptop. But then as in the original problem report, I needed two attempts to establish NM connection.