ssh'ing remotely: Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.xcb: could not connect to display :0
Solved
General and Desktop
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Hi -- for various reasons I am trying to ssh into my desktop to start krfb (remote desktop sofware). I'm using Kubuntu 21.04.
If I have already logged in on my desktop (via standard sddm GUI) I can do all this and it works. I can ssh in and start krfb and it starts fine.
On the other hand, If I ssh in to the desktop before logging in on the desktop and I do:
export DISPLAY=:0
startx &
krfb --nodialog &...it does not work when I run krfb. See below for full QT_DEBUG_PLUGINS output, but the key error seems to be:
Got keys from plugin meta data ("xcb") QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ... loaded library "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so" Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.xcb: could not connect to display :0 qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.I have googled around and found various recommendations to reinstall things and so on, but I suspect that with my situation this is due to some kind of configuration not being set up properly because of the unusual way that I'm starting the desktop session.
Is there anything obvious I'm missing about how Qt is configured that may be affected by my strange login method?
Is there anything else I can do to try to debug this situation?
Perhaps better/smarter ways to start a regular desktop KDE session besides "startx" that might configure things properly?
I have not installd any qt packages beyond the default packages installed with Kubuntu. (It's possible that I installed qt4-default years ago, but I think not on this system.)
Thanks!
QFactoryLoader::QFactoryLoader() checking directory path "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms" ... QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqeglfs.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqeglfs.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "eglfs" ] }, "archreq": 0, "className": "QEglFSIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("eglfs") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqlinuxfb.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqlinuxfb.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "linuxfb" ] }, "archreq": 0, "className": "QLinuxFbIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("linuxfb") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimal.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimal.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "minimal" ] }, "archreq": 0, "className": "QMinimalIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("minimal") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimalegl.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimalegl.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "minimalegl" ] }, "archreq": 0, "className": "QMinimalEglIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("minimalegl") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqoffscreen.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqoffscreen.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "offscreen" ] }, "archreq": 0, "className": "QOffscreenIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("offscreen") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqvnc.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqvnc.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "vnc" ] }, "archreq": 0, "className": "QVncIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("vnc") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-egl.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-egl.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "wayland-egl" ] }, "archreq": 0, "className": "QWaylandEglPlatformIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("wayland-egl") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-generic.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-generic.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "wayland" ] }, "archreq": 0, "className": "QWaylandIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("wayland") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-egl.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-egl.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "wayland-xcomposite-egl" ] }, "archreq": 0, "className": "QWaylandXCompositeEglPlatformIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("wayland-xcomposite-egl") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-glx.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-glx.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "wayland-xcomposite-glx" ] }, "archreq": 0, "className": "QWaylandXCompositeGlxPlatformIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("wayland-xcomposite-glx") QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so" Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so, metadata= { "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "xcb" ] }, "archreq": 0, "className": "QXcbIntegrationPlugin", "debug": false, "version": 331520 } Got keys from plugin meta data ("xcb") QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ... loaded library "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so" Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.xcb: could not connect to display :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, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.