Browser Extension stopped working after changing local IP address.

[RubberDuckyDJ]

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Brief Summary

After I changed my local IP address, KeePassXC stopped connecting to the browser extension

System Info

Operating System: Nobara Linux 43
KDE Plasma Version: 6.6.2
KDE Frameworks Version: 6.24.0
Qt Version: 6.10.2
Kernel Version: 6.19.11-201.nobara.fc43.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 32 GiB of RAM (31.2 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 3060 Ti
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: B550 AORUS ELITE

KeePassXC Version

2.7.12-1.fc43

Output from the the Firefox developer tools console for the extension while trying to connect

Source map error: can't access property "sources", map is undefined
Resource URL: moz-extension://16a31466-4b2f-48a0-b44c-80a057f64ff9/common/browser-polyfill.min.js
Source Map URL: browser-polyfill.min.js.map
KeePassXC-Browser: Connecting to native messaging host org.keepassxc.keepassxc_browser client.js:383:13
[Error ] KeePassXC-Browser - Failed to connect: Unknown error global.js:194:13
[Error event.js:96] KeePassXC-Browser - changePublicKeys failed: TypeError: can't access property "postMessage", keepassClient.nativePort is null global.js:194:13
[Error keepass.js:265] KeePassXC-Browser - 5: Cannot connect to KeePassXC. Check that browser integration is enabled in KeePassXC settings.

Full Developer Console Log

console-export-2026-4-16_1-36-17.log

Log from Keepass Program

kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "Save All" msgid_plural: "" msgctxt: "@action:button"
kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "&Yes" msgid_plural: "" msgctxt: "@action:button"
kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "Yes to All" msgid_plural: "" msgctxt: "@action:button"
kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "&No" msgid_plural: "" msgctxt: "@action:button"
kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "No to All" msgid_plural: "" msgctxt: "@action:button"
kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "Abort" msgid_plural: "" msgctxt: "@action:button"
kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "Retry" msgid_plural: "" msgctxt: "@action:button"
kf.i18n: KLocalizedString: Using an empty domain, fix the code. msgid: "Ignore" msgid_plural: "" msgctxt: "@action:button"
qt.qpa.wayland: Wayland does not support QWindow::requestActivate()
qt.qpa.wayland: Wayland does not support QWindow::requestActivate()

Expected Versus Actual Behavior

Changing my local IP address shouldn't effect the ability of KeePassXC to connect to the browser extension.

Steps to Reproduce

1. Attempt to auto-fill a password
2. Realize the browser extension won't connect to the program
3. 🫩

KeePassXC-Browser Debug Information

KeePassXC - unknown
KeePassXC-Browser - 1.10.1
Operating system: Linux x86_64
Browser: Mozilla Firefox 148.0

[varjolintu]

And your browser is..? And installed via what, repo/Flatpak/Snap..? The native messaging with KeePassXC is using local Unix sockets only, so changing your IP shouldn't affect anything.

[RubberDuckyDJ]

And your browser is..? And installed via what, repo/Flatpak/Snap..? The native messaging with KeePassXC is using local Unix sockets only, so changing your IP shouldn't affect anything.

I'm using Firefox 148.0.2-1.fc43 from the Nobara DNF repository.

[varjolintu]

Try disabling and re-enabling the browser integration support in KeePassXC. After that remove all connections from both KeePassXC and the extension, and reconnect them again.

For me this sounds like an issue with a recent Firefox update. Sometimes it breaks the socket connection with KeePassXC.

[RubberDuckyDJ]

Try disabling and re-enabling the browser integration support in KeePassXC. After that remove all connections from both KeePassXC and the extension, and reconnect them again.

For me this sounds like an issue with a recent Firefox update. Sometimes it breaks the socket connection with KeePassXC.

I removed the connection from the extension settings and disabled and renabled browser integration in keepassxc but the issue still persists.

[varjolintu]

Go through this guide and report your findings:
https://github.com/keepassxreboot/keepassxc-browser/wiki/Troubleshooting-guide

[RubberDuckyDJ]

org.keepassxc.keepassxc_browser.json is in ~/.mozilla/native-messaging-hosts/

I am not using flatpak or snap

org.keepassxc.keepassxc_browser.json contains keepassxc-browser@keepassxc.org under allowed_extensions

keepassxc-proxy is not launched by default but launching it doesn't fix the problem

The command 'sudo strace -f -p $(pgrep firefox) 2>&1 | grep keepass' doesn't output anything

/run/user/1000/app/org.keepassxc.KeePassXC/ contains org.keepassxc.KeePassXC.BrowserServer and there is a symbolic link at /run/user/1000/

I am not using firejail

widget.use-xdg-desktop-portal.native-messaging is set to 2

The output of debugging the extension was pasted in the original issue

This is the contents of my firefox apparmor file

# This profile allows everything and only exists to give the
# application a name instead of having the label "unconfined"

abi <abi/4.0>,
include <tunables/global>

profile firefox /{usr/lib/firefox{,-esr,-beta,-devedition,-nightly},opt/firefox}/firefox{,-esr,-bin} flags=(unconfined) {
  userns,

  # Site-specific additions and overrides. See local/README for details.
  include if exists <local/firefox>
}

[varjolintu]

So AppArmor is in use? And you have these? https://github.com/keepassxreboot/keepassxc-browser/wiki/Troubleshooting-guide#6-apparmor-with-ubuntu. Not sure if those applies to your distro.

[RubberDuckyDJ]

Ubuntu is the only distro I know of that ships with a configured app armor profile for firefox.
My distro's apparmor profile for firefox isn't configured so it shouldn't be blocking anything.
But just to make sure that nothing was being blocked I ran sudo journalctl -t kernel | grep 'apparmor="DENIED"' | grep "$(which keepassxc-proxy)" and sure enough, nothing.