I'm using the GUI to open a hotspot in Ubuntu 23.04 (Settings > Wifi > ... > Turn on Wifi hotspot). Then the GUI shows me the info page of the hotspot, but when I wait for a few seconds, the hotspot automatically terminates and I get the notification "Activation of network connection failed".
I tried downgrading the wpasupplicant package to version 2:2.9.0-21build1 as suggested in this answer and this blog post and it worked. But it doesn't always work. I have to try multiple times before it is stable. This answer suggests to turn off the firewall, but in my case ufw status prints 'inactive'.
Following the suggestion in this question, I checked journalctl --follow and found the following messages while trying and failing to create a hotspot:
Sep 11 17:40:15 MyComputer NetworkManager[1271]: <info> [1694425215.9796] audit: op="connection-update" uuid="80ac3828-83f1-44fd-ba7a-906207600c48" name="Hotspot" args="connection.timestamp" pid=10109 uid=1000 result="success"
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.0013] device (wlp2s0): disconnecting for new activation request.
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.0014] device (wlp2s0): state change: activated -> deactivating (reason 'new-activation', sys-iface-state: 'managed')
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.0052] audit: op="connection-activate" uuid="80ac3828-83f1-44fd-ba7a-906207600c48" name="Hotspot" pid=10109 uid=1000 result="success"
Sep 11 17:40:16 MyComputer dbus-daemon[1203]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.12' (uid=0 pid=1271 comm="/usr/sbin/NetworkManager --no-daemon" label="unconfined")
Sep 11 17:40:16 MyComputer systemd[1]: Starting NetworkManager-dispatcher.service - Network Manager Script Dispatcher Service...
Sep 11 17:40:16 MyComputer dbus-daemon[1203]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 11 17:40:16 MyComputer systemd[1]: Started NetworkManager-dispatcher.service - Network Manager Script Dispatcher Service.
Sep 11 17:40:16 MyComputer kernel: wlp2s0: deauthenticating from xx:xx:xx:xx:xx:xx by local choice (Reason: 3=DEAUTH_LEAVING)
Sep 11 17:40:16 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-DISCONNECTED bssid=xx:xx:xx:xx:xx:xx reason=3 locally_generated=1
Sep 11 17:40:16 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=CORE type=WORLD
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.2119] device (wlp2s0): state change: deactivating -> disconnected (reason 'new-activation', sys-iface-state: 'managed')
Sep 11 17:40:16 MyComputer avahi-daemon[1201]: Withdrawing address record for fe80::c5eb:c1b5:97da:9fd1 on wlp2s0.
Sep 11 17:40:16 MyComputer avahi-daemon[1201]: Leaving mDNS multicast group on interface wlp2s0.IPv6 with address fe80::c5eb:c1b5:97da:9fd1.
Sep 11 17:40:16 MyComputer avahi-daemon[1201]: Interface wlp2s0.IPv6 no longer relevant for mDNS.
Sep 11 17:40:16 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.2416] dhcp4 (wlp2s0): canceled DHCP transaction
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.2417] dhcp4 (wlp2s0): activation: beginning transaction (timeout in 45 seconds)
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.2417] dhcp4 (wlp2s0): state changed no lease
Sep 11 17:40:16 MyComputer wpa_supplicant[1274]: wlp2s0: Reject scan trigger since one is already pending
Sep 11 17:40:16 MyComputer avahi-daemon[1201]: Withdrawing address record for 7.250.140.92 on wlp2s0.
Sep 11 17:40:16 MyComputer avahi-daemon[1201]: Leaving mDNS multicast group on interface wlp2s0.IPv4 with address 7.250.140.92.
Sep 11 17:40:16 MyComputer avahi-daemon[1201]: Interface wlp2s0.IPv4 no longer relevant for mDNS.
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.2961] device (wlp2s0): Activation: starting connection 'Hotspot' (80ac3828-83f1-44fd-ba7a-906207600c48)
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.2969] device (wlp2s0): supplicant interface state: completed -> disconnected
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.2970] device (p2p-dev-wlp2s0): supplicant management interface state: completed -> disconnected
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3059] device (wlp2s0): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3066] manager: NetworkManager state is now CONNECTING
Sep 11 17:40:16 MyComputer openconnect[8344]: BYE-Paket senden: Aborted by caller
Sep 11 17:40:16 MyComputer systemd-resolved[1121]: vpn0: Bus client reset search domain list.
Sep 11 17:40:16 MyComputer systemd-resolved[1121]: vpn0: Bus client set default route setting: no
Sep 11 17:40:16 MyComputer openconnect[8344]: User cancelled (SIGINT/SIGTERM); exiting.
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3162] device (wlp2s0): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3165] device (wlp2s0): Activation: (wifi) access point 'Hotspot' has security, but secrets are required.
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3165] device (wlp2s0): state change: config -> need-auth (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:16 MyComputer kernel: IPv6: ADDRCONF(NETDEV_CHANGE): vpn0: link becomes ready
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3201] device (vpn0): state change: activated -> unmanaged (reason 'connection-assumed', sys-iface-state: 'external')
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3210] device (wlp2s0): state change: need-auth -> prepare (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3222] device (wlp2s0): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3226] device (wlp2s0): Activation: (wifi) connection 'Hotspot' has security, and secrets exist. No new secrets needed.
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'ssid' value 'MyComputer'
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'mode' value '2'
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'frequency' value '2472'
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'key_mgmt' value 'WPA-PSK WPA-PSK-SHA256'
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'psk' value '<hidden>'
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'proto' value 'RSN'
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'pairwise' value 'CCMP'
Sep 11 17:40:16 MyComputer NetworkManager[1271]: <info> [1694425216.3227] Config: added 'group' value 'CCMP'
Sep 11 17:40:16 MyComputer systemd-resolved[1121]: vpn0: Bus client reset DNS server list.
Sep 11 17:40:16 MyComputer wpa_supplicant[1274]: Note: nl80211 driver interface is not designed to be used with ap_scan=2; this can result in connection failures
Sep 11 17:40:16 MyComputer wpa_supplicant[1274]: wlp2s0: Failed to start AP functionality
Sep 11 17:40:16 MyComputer wpa_supplicant[1274]: wlp2s0: Failed to start AP functionality
Sep 11 17:40:26 MyComputer systemd[1]: NetworkManager-dispatcher.service: Deactivated successfully.
Sep 11 17:40:41 MyComputer NetworkManager[1271]: <warn> [1694425241.3069] device (wlp2s0): Activation: (wifi) Hotspot network creation took too long, failing activation
Sep 11 17:40:41 MyComputer NetworkManager[1271]: <info> [1694425241.3070] device (wlp2s0): state change: config -> failed (reason 'supplicant-timeout', sys-iface-state: 'managed')
Sep 11 17:40:41 MyComputer NetworkManager[1271]: <info> [1694425241.3076] manager: NetworkManager state is now CONNECTED_LOCAL
Sep 11 17:40:41 MyComputer NetworkManager[1271]: <warn> [1694425241.3080] device (wlp2s0): Activation: failed for connection 'Hotspot'
Sep 11 17:40:41 MyComputer NetworkManager[1271]: <info> [1694425241.3084] device (wlp2s0): state change: failed -> disconnected (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:41 MyComputer wpa_supplicant[1274]: wlp2s0: Reject scan trigger since one is already pending
Sep 11 17:40:42 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:42 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:42 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:42 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:42 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:44 MyComputer systemd[1]: systemd-hostnamed.service: Deactivated successfully.
Sep 11 17:40:45 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:45 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:45 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:45 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.1988] policy: auto-activating connection 'HomeWifi' (7e12d06a-4979-4831-a41b-16b38531724c)
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.1992] device (wlp2s0): Activation: starting connection 'HomeWifi' (7e12d06a-4979-4831-a41b-16b38531724c)
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.1993] device (wlp2s0): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.1995] manager: NetworkManager state is now CONNECTING
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.1998] device (wlp2s0): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2000] device (wlp2s0): Activation: (wifi) connection 'HomeWifi' requires no security. No secrets needed.
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2000] Config: added 'ssid' value 'HomeWifi'
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2000] Config: added 'scan_ssid' value '1'
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2001] Config: added 'bgscan' value 'simple:30:-70:86400'
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2001] Config: added 'key_mgmt' value 'NONE'
Sep 11 17:40:46 MyComputer wpa_supplicant[1274]: wlp2s0: SME: Trying to authenticate with xx:xx:xx:xx:xx:xx (SSID='HomeWifi' freq=5220 MHz)
Sep 11 17:40:46 MyComputer kernel: wlp2s0: authenticate with xx:xx:xx:xx:xx:xx
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2560] device (wlp2s0): supplicant interface state: disconnected -> authenticating
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2560] device (p2p-dev-wlp2s0): supplicant management interface state: disconnected -> authenticating
Sep 11 17:40:46 MyComputer wpa_supplicant[1274]: wlp2s0: Trying to associate with xx:xx:xx:xx:xx:xx (SSID='HomeWifi' freq=5220 MHz)
Sep 11 17:40:46 MyComputer kernel: wlp2s0: send auth to xx:xx:xx:xx:xx:xx (try 1/3)
Sep 11 17:40:46 MyComputer kernel: wlp2s0: authenticated
Sep 11 17:40:46 MyComputer kernel: wlp2s0: associate with xx:xx:xx:xx:xx:xx (try 1/3)
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2580] device (wlp2s0): supplicant interface state: authenticating -> associating
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.2580] device (p2p-dev-wlp2s0): supplicant management interface state: authenticating -> associating
Sep 11 17:40:46 MyComputer kernel: wlp2s0: RX AssocResp from xx:xx:xx:xx:xx:xx (capab=0x1501 status=0 aid=1)
Sep 11 17:40:46 MyComputer kernel: wlp2s0: associated
Sep 11 17:40:46 MyComputer wpa_supplicant[1274]: wlp2s0: Associated with xx:xx:xx:xx:xx:xx
Sep 11 17:40:46 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-CONNECTED - Connection to xx:xx:xx:xx:xx:xx completed [id=0 id_str=]
Sep 11 17:40:46 MyComputer kernel: ath: EEPROM regdomain: 0x809c
Sep 11 17:40:46 MyComputer kernel: ath: EEPROM indicates we should expect a country code
Sep 11 17:40:46 MyComputer kernel: ath: doing EEPROM country->regdmn map search
Sep 11 17:40:46 MyComputer kernel: ath: country maps to regdmn code: 0x52
Sep 11 17:40:46 MyComputer kernel: ath: Country alpha2 being used: CN
Sep 11 17:40:46 MyComputer kernel: ath: Regpair used: 0x52
Sep 11 17:40:46 MyComputer kernel: ath: regdomain 0x809c dynamically updated by country element
Sep 11 17:40:46 MyComputer kernel: IPv6: ADDRCONF(NETDEV_CHANGE): wlp2s0: link becomes ready
Sep 11 17:40:46 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
Sep 11 17:40:46 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=COUNTRY_IE type=COUNTRY alpha2=CN
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3464] device (wlp2s0): supplicant interface state: associating -> completed
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3465] device (wlp2s0): Activation: (wifi) Stage 2 of 5 (Device Configure) successful. Connected to wireless network "HomeWifi"
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3466] device (p2p-dev-wlp2s0): supplicant management interface state: associating -> completed
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3473] device (wlp2s0): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3489] dhcp4 (wlp2s0): activation: beginning transaction (timeout in 45 seconds)
Sep 11 17:40:46 MyComputer avahi-daemon[1201]: Joining mDNS multicast group on interface wlp2s0.IPv6 with address fe80::c5eb:c1b5:97da:9fd1.
Sep 11 17:40:46 MyComputer kernel: wlp2s0: Limiting TX power to 23 (23 - 0) dBm as advertised by xx:xx:xx:xx:xx:xx
Sep 11 17:40:46 MyComputer avahi-daemon[1201]: New relevant interface wlp2s0.IPv6 for mDNS.
Sep 11 17:40:46 MyComputer avahi-daemon[1201]: Registering new address record for fe80::c5eb:c1b5:97da:9fd1 on wlp2s0.*.
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3671] dhcp4 (wlp2s0): state changed new lease, address=7.250.140.92
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3683] policy: set 'HomeWifi' (wlp2s0) as default for IPv4 routing and DNS
Sep 11 17:40:46 MyComputer avahi-daemon[1201]: Joining mDNS multicast group on interface wlp2s0.IPv4 with address 7.250.140.92.
Sep 11 17:40:46 MyComputer avahi-daemon[1201]: New relevant interface wlp2s0.IPv4 for mDNS.
Sep 11 17:40:46 MyComputer avahi-daemon[1201]: Registering new address record for 7.250.140.92 on wlp2s0.IPv4.
Sep 11 17:40:46 MyComputer dbus-daemon[1203]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.12' (uid=0 pid=1271 comm="/usr/sbin/NetworkManager --no-daemon" label="unconfined")
Sep 11 17:40:46 MyComputer systemd-resolved[1121]: wlp2s0: Bus client set default route setting: yes
Sep 11 17:40:46 MyComputer systemd-resolved[1121]: wlp2s0: Bus client set DNS server list to: 114.114.114.114, 114.114.115.115, 223.5.5.5, 223.6.6.6, 180.76.76.76
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.3946] device (wlp2s0): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:46 MyComputer systemd[1]: Starting NetworkManager-dispatcher.service - Network Manager Script Dispatcher Service...
Sep 11 17:40:46 MyComputer dbus-daemon[1203]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 11 17:40:46 MyComputer systemd[1]: Started NetworkManager-dispatcher.service - Network Manager Script Dispatcher Service.
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.4570] device (wlp2s0): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.4573] device (wlp2s0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'managed')
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.4577] manager: NetworkManager state is now CONNECTED_SITE
Sep 11 17:40:46 MyComputer NetworkManager[1271]: <info> [1694425246.4593] device (wlp2s0): Activation: successful, device activated.
Sep 11 17:40:46 MyComputer wpa_supplicant[1274]: wlp2s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-55 noise=-101 txrate=104000
Sep 11 17:40:48 MyComputer NetworkManager[1271]: <info> [1694425248.0783] manager: NetworkManager state is now CONNECTED_GLOBAL
In this log, you can see that it first disconnects from the current Wifi and VPN, creates a hotspot, fails to do so, and connects back to the original Wifi. The following lines look especially interesting:
wpa_supplicant[1274]: wlp2s0: Failed to start AP functionality
NetworkManager[1271]: <warn> [1694425241.3069] device (wlp2s0): Activation: (wifi) Hotspot network creation took too long, failing activation
NetworkManager[1271]: <info> [1694425241.3070] device (wlp2s0): state change: config -> failed (reason 'supplicant-timeout', sys-iface-state: 'managed')
I want to note that I was able to reliably operate hotspots on this device on Ubuntu 22.04 (or earlier) some time ago. So, the network card should be able to do this.
