Address already in use

[Bsd-us]

hey, I don't know if this applet is meant to work on other operating systems but I have this issue after installing with "just" on cachyos

april 25 13:01:13 cache kdeconnect-service[5872]: thread 'main' (5872) panicked at kdeconnect-core/src/transport.rs:299:29:
april 25 13:01:13 cache kdeconnect-service[5872]: failed to bind UDP socket after 10 attempts: Address already in use (os error 98)
april 25 13:01:13 cache kdeconnect-service[5872]: note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
april 25 12:59:23 cache kdeconnect-service[1535]: 2026-04-25T10:59:23.042332Z  WARN zbus::connection: Requesting name `io.github.hepp3n.kdeconnect` before setting up the object server. Method calls arriving before interfaces are registered may be lost. Consider using `connection::Builder::serve_at()` and `::name()` instead.
april 25 13:00:46 cache kdeconnect-service[4824]: 2026-04-25T11:00:46.753454Z  WARN kdeconnect_core::transport: UDP bind failed (attempt 1), retrying in 1s: Address already in use (os error 98)
april 25 13:00:47 cache kdeconnect-service[4824]: 2026-04-25T11:00:47.755163Z  WARN kdeconnect_core::transport: UDP bind failed (attempt 2), retrying in 1s: Address already in use (os error 98)

Logs from systemd's journalctl SYSLOG_IDENTIFIER=kdeconnect-service

This seemed related to #8 so I tried using the applet in a dock instead of the panel but it didn't help unfortunately
Any ideas ? thank you for your work anyway for bringing this to cosmic !

[M4L-C0ntent]

Hi,

The applet is mainly tested within PopOS but should work on all distros with the cosmic desktop via flatpak. If installed from source there could be quirks between differences in distros. Looking at the log you submitted it seems that there is another instance already running. I would suggest using the flatpak version but you could try running the source install with the systemd option. This may resolve the multiple instance issue but I can not be sure on your distro.

Try:
just uninstall
just build (In case you cleaned cargo)
just install-systemd
just enable-service

For good measure also log out and back in.
Let me know if this helps. There are other options I am considering as a safe guard.

Thank you for testing.

[hepp3n]

I wonder, since it's cachyos, it might be kdeconnect daemon installed or running. Which probably causes conflict.

[M4L-C0ntent]

I wonder, since it's cachyos, it might be kdeconnect daemon installed or running. Which probably causes conflict.

I'm not too familiar with cachyos but if comes with plasma installed by default and you don't disable the kdeconnect daemon when running cosmic it is quite possible.

Thanks @hepp3n

[Bsd-us]

thank you for your answers !
cachyos has now cosmic out of the box as an option which is what I have so I don't feel like this is the problem, I never had plasma
I will test more in the next days but from what I remember I actually did install with ujust install-systemd which is why I was sending journalctl logs
I'd like to avoid installing flatpak only for this applet so I am up for the safe guard options :)

[M4L-C0ntent]

Like I mentioned before I am not familiar with cachyos but if I remember correctly from bazzite - ujust is meant run system-wide task. Have you tried using standard just to install? The applet is meant to be only installed in the userspace and not system-wide. I would try first to uninstall the applet with ujust and then install with standard just.

[Bsd-us]

oh I'm sorry for the confusion I never had ujust on cachyos I used the just command from the readme (I had bazzite before so I bugged out x)
I edited my initial message to correct that

[M4L-C0ntent]

Well I would still suggest using the flatpak version. If source is not installed on PopOS, it is bounded to have some quirks due to the differences within the OS. The safe guards I mentioned earlier is something I was already considering doing as a addition to what is already in place (basically more efficient) which may help your case but I can not be sure.

[hepp3n]

Hey,
I just looked into this issue. It's comes from this lines: https://github.com/hepp3n/kdeconnect/blob/master/cosmic-ext-connect-applet/src/main.rs#L458-L462
We can't spawn kdeconnect-service manually. It properly spawned in flatpak sandbox by it's own. At least for me :P
When we do this, it fails, because previously after pinning applet to panel, the dbus service is running and UDP socket is bound.

[hepp3n]

@Bsd-us I made a PR with disabled those lines, can you test it, please?

#43

Please make sure before, you uninstalled any kdeconnect from us. And killall kdeconnect-service

Or just reboot after uninstalling. Thanks!

[Bsd-us]

hey thank you so much for digging this up, but as I mentioned before I want to avoid installing flatpak, I'm really sorry...

I tried a lot of things, rebooting after uninstall, using install systemd, all of this as a user, but got the same error

[hepp3n]

Ah well, sorry then. Anyway, this should works also on normal installation.
The same code applies to flatpak/native. I need to look into justfile to see installation method for native. Not remember correctly.

[hepp3n]

@Bsd-us Ok, so. Please if you can, of course. Test mentioned PR.
Use this just commands to install instead of flatpak one.

just build && just install

You might need to reboot, or not. Not sure to be honest if dbus service will be activated after pinning applet.

[Bsd-us]

Ah I didn't think it would work for native too, here's what I tried then

just uninstall && cd .. && rm -rf kdeconnect
# reboot
git clone https://github.com/hepp3n/kdeconnect.git -b testing-service && cd kdeconnect
just build
just install-systemd
just enable-service
# add applet to my dock
# can't see any device even though on the app I can ping by ip my pc
# reboot
# tried again: same issue

Though there is new logs, no common lines with before and here's the one that is repeated :

> journalctl SYSLOG_IDENTIFIER=kdeconnect-service
april 30 16:41:06 cache kdeconnect-service[1407]: 2026-04-30T14:41:06.076000Z  WARN zbus::connection: Requesting name `io.github.hepp3n.kdeconnect` before setting up the object server. Method calls arriving before interfaces are registered may be lost. Consider using `connection::Builder::serve_at()` and `::name()` instead.

[hepp3n]

Thank you! Need to investigate it further. I did not try systemd method myself tho. So need to check this.

[hepp3n]

@Bsd-us,
Well. Just tried again, seems to works.
Added daemon-reload command for enabling systemd service. It might help if files are changed on the fly.

1. First uninstall again all kdeconnect components, just uninstall
2. Reboot. (just to be sure :P)
3. Check if 1716 port is not occupied: netstat -tlun | grep -i 1716
   • should not return anything, if you see some output, this means port is already used :/
4. git clone https://github.com/hepp3n/kdeconnect.git -b testing-service && cd kdeconnect
5. just build
6. just install-systemd
7. Check if service is installed properly and NOT STARTED
   • systemctl --user status kdeconnect-service
8. if you see it's started just pin applet to panel if not just enable-service

I'm using my custom Ubuntu image, so it's not PopOS either.