Mozilla VPN does not allow traffic

[mcasperson]

Describe the bug
Using both the UI and the cli, the VPN will connect but report no signal. This happens on all VPN servers I tried.

VPN version:
2.31.0 (2.31.0~rc20250916222335-static1)

Affected Platforms:
Linux Mint 22.2

Prerequisites:
<Optional: Any special steps taken not related to the app to trigger the bug>

Steps to reproduce:

1. Connect to the VPN via the UI
2. The connection appears to succeed
3. After about a second, the UI reports no signal

Expected result:
The VPN should connect

Actual result:
The VPN does not connect

Additional notes:
I have a second machine that connects to the VPN successfully. The difference in the logs on the failing machine appears to be this:

19.09.2025 14:36:57.621] (LinuxPingSender) Error: Socket creation error:  Operation not permitted
[19.09.2025 14:36:57.621] (PingHelper) Warning: PingSenderFactory is not valid, trying DnsPingSender.
[19.09.2025 14:36:57.621] (DnsPingSender) Error: Unable to bind UDP socket. Socket state: QAbstractSocket::UnconnectedState
[19.09.2025 14:36:57.621] (DnsPingSender) Debug: UDP socket bound to:

The error Error: Unable to bind UDP socket. Socket state: QAbstractSocket::UnconnectedState is not present on the machine that works.

Also, the line Debug: UDP socket bound to: on the failing machine is Debug: UDP socket bound to: 0.0.0.0 on the working machine.

mozillavpn-2025-9-19_2.log

┆Issue is synchronized with this Jira Bug

[mcasperson]

For context, these are the logs for a machine that successfully connects to the VPN. Both connect to the same underlying network, which would tend to rule out "environmental" factors in this issue.

mozillavpn-2025-9-19.log

[oskirby]

On the machine that doesn't connect, it seems like there are no logs from the daemon process. This might indicate that it isn't running or has crashed in some way that would prevent a successful connection.

You can check the status of the daemon using the systemctl status mozillavpn command. If running, it should report something like the following:

● mozillavpn.service - MozillaVPN D-Bus service
     Loaded: loaded (/usr/lib/systemd/system/mozillavpn.service; disabled; preset: disabled)
    Drop-In: /usr/lib/systemd/system/service.d
             └─10-timeout-abort.conf
     Active: active (running) since Thu 2025-09-18 14:49:28 PDT; 19h ago
 Invocation: 62ade8f45205445eb5e270573ad91fd6
   Main PID: 60816 (mozillavpn)
      Tasks: 8 (limit: 17532)
     Memory: 5.3M (peak: 8.6M, swap: 2.5M, swap peak: 2.5M)
        CPU: 336ms
     CGroup: /system.slice/mozillavpn.service
             └─60816 /usr/local/bin/mozillavpn linuxdaemon

Sep 19 09:45:54 tungsten mozillavpn[60816]: [19.09.2025 09:45:54.113] (AppTracker) Debug: Control group created: /user.slice/user-1000.slice/user@1000.service/app.slice/app-flatpak-co>
Sep 19 09:45:54 tungsten mozillavpn[60816]: [19.09.2025 09:45:54.114] (DBusService) Debug: tracking: /user.slice/user-1000.slice/user@1000.service/app.slice/app-flatpak-com.visualstud>
Sep 19 09:47:04 tungsten mozillavpn[60816]: [19.09.2025 09:47:04.582] (AppTracker) Debug: Control group created: /user.slice/user-1000.slice/user@1000.service/app.slice/app-flatpak-or>
Sep 19 09:47:04 tungsten mozillavpn[60816]: [19.09.2025 09:47:04.583] (DBusService) Debug: tracking: /user.slice/user-1000.slice/user@1000.service/app.slice/app-flatpak-org.mozilla.vp>
Sep 19 09:53:16 tungsten mozillavpn[60816]: [19.09.2025 09:53:16.123] (AppTracker) Debug: Control group removed: /user.slice/user-1000.slice/user@1000.service/app.slice/app-flatpak-or>
Sep 19 09:53:16 tungsten mozillavpn[60816]: [19.09.2025 09:53:16.123] (DBusService) Debug: terminate: /user.slice/user-1000.slice/user@1000.service/app.slice/app-flatpak-org.mozilla.v>
Sep 19 09:53:28 tungsten mozillavpn[60816]: [19.09.2025 09:53:28.593] (DBusService) Debug: User 0 state is: opening
Sep 19 09:53:28 tungsten mozillavpn[60816]: [19.09.2025 09:53:28.699] (DBusService) Debug: User 0 state is: online
Sep 19 09:53:28 tungsten mozillavpn[60816]: [19.09.2025 09:53:28.700] (AppTracker) Debug: User created uid: 0 at: /run/user/0
Sep 19 09:53:28 tungsten mozillavpn[60816]: [19.09.2025 09:53:28.700] (AppTracker) Debug: Connection to unix:path=/run/user/0/bus

You should also be able to retrieve the logs from the daemon manually. They should exist on disk at /var/log/mozillavpn.log There might be more information there for us to dig through.

[mcasperson]

Hi @oskirby , thanks for the additional info.

This is the status of the mozillavpn service:

$ sudo systemctl status mozillavpn
● mozillavpn.service - MozillaVPN D-Bus service
     Loaded: loaded (/usr/lib/systemd/system/mozillavpn.service; enabled; preset: enabled)
     Active: active (running) since Sat 2025-09-20 06:56:28 AEST; 22s ago
   Main PID: 2095315 (mozillavpn)
      Tasks: 8 (limit: 154008)
     Memory: 14.1M (peak: 15.3M)
        CPU: 47ms
     CGroup: /system.slice/mozillavpn.service
             └─2095315 /usr/bin/mozillavpn linuxdaemon

Sep 20 06:56:28 matthew-System-Product-Name systemd[1]: Starting mozillavpn.service - MozillaVPN D-Bus service...
Sep 20 06:56:28 matthew-System-Product-Name systemd[1]: Started mozillavpn.service - MozillaVPN D-Bus service.

I also restarted the service just to make sure, and the issue persists.

This is the log file:

mozillavpn.log

[mcasperson]

This could be related. The ip a command doesn't show a moz0 adapter on the machine that fails to connect:

$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute 
       valid_lft forever preferred_lft forever
2: enp12s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 60:cf:84:8a:5c:59 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.118/24 brd 192.168.1.255 scope global dynamic noprefixroute enp12s0
       valid_lft 59149sec preferred_lft 59149sec
    inet6 fd41:ea9:f40e:9b96:c8bd:165d:78af:cac3/64 scope global temporary dynamic 
       valid_lft 1737sec preferred_lft 1737sec
    inet6 fd41:ea9:f40e:9b96:6a70:4bad:d5c4:dc66/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 1737sec preferred_lft 1737sec
    inet6 fe80::456c:9d0d:5450:7deb/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: enp11s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether 60:cf:84:ac:17:26 brd ff:ff:ff:ff:ff:ff