Flatpak deosn't start app anymore. How to troubleshoot?

Hello there,
I installed flatpak few months ago and run fine, not every day, 4-5 app until now.
When I click on any icon, the “hourglass” spin around 5-7s then stop. Nothing happen.
This looks to be flatpak itself issue as all the apps can’t start.

I don’t have any clue how to troubleshoot flatpak.

2023-03-16T21:52:27.673209+01:00 localhost systemd[1296]: Started app-flatpak-io.posidon.Paper-3872.scope.
2023-03-16T21:52:27.717155+01:00 localhost dbus-daemon[1367]: [session uid=1000 pid=1367] Activating via systemd: service name='org.freedesktop.impl.portal.desktop.gtk' unit='xdg-desktop-portal-gtk.service' requested by ':1.21' (uid=1000 pid=1562 comm="/usr/lib/xdg-desktop-portal ")
2023-03-16T21:52:27.718060+01:00 localhost systemd[1296]: Starting Portal service (GTK+/GNOME implementation)...
2023-03-16T21:52:27.749297+01:00 localhost dbus-daemon[1367]: [session uid=1000 pid=1367] Successfully activated service 'org.freedesktop.impl.portal.desktop.gtk'
2023-03-16T21:52:27.749393+01:00 localhost systemd[1296]: Started Portal service (GTK+/GNOME implementation).
2023-03-16T21:52:28.744073+01:00 localhost xdg-desktop-portal-gtk[3891]: Invalid MIT-MAGIC-COOKIE-1 keyInvalid MIT-MAGIC-COOKIE-1 key
2023-03-16T21:52:50.329442+01:00 localhost sudo: gkr-pam: unable to locate daemon control file

On another box, with Leap 154 as well, I got the same issue. Coincidence?
Any help is welcome

Basic checks, like starting from terminal and looking for output, already done?

Thanks hui

~> flatpak run io.posidon.Paper
Invalid MIT-MAGIC-COOKIE-1 key

(io.posidon.Paper:2): Gtk-WARNING **: 09:34:02.200: cannot open display: :99.0

~> flatpak run eu.scarpetta.PDFMixTool
Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.xcb: could not connect to display :99.0
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

Maybe this could help

~> xhost +
Invalid MIT-MAGIC-COOKIE-1 keyaccess control disabled, clients can connect from any host

For information

~> flatpak --version
Flatpak 1.12.5


@nano-o nano-o mentioned this issue Nov 16, 2022

Flatpak apps stop launching if an app is using display :99 (fixed in Flatpak 1.14) pop-os/flatpak#5

Do you have application(s) that allocate display number :99?

How could I know that?

Have you tried the solution here? Cannot run flatpaks anymore - #3 by tannington

1 Like

Thank you a lot

Working fine now.

1 Like