Firefox rfuses to start YouTube display

[BertN45]

Firefox starts to build the buffer, but is does not display anything. See screenshot.

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: firefox 88.0.1+build1-0ubuntu0.21.04.2
ProcVersionSignature: Ubuntu 5.11.0-17.18-generic 5.11.12
Uname: Linux 5.11.0-17-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
AddonCompatCheckDisabled: False
ApportVersion: 2.20.11-0ubuntu65
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: bertadmin 4040 F.... pulseaudio
 /dev/snd/pcmC1D0p: bertadmin 4040 F...m pulseaudio
 /dev/snd/controlC0: bertadmin 4040 F.... pulseaudio
BuildID: 20210504152106
CasperMD5CheckResult: unknown
Channel: Unavailable
CurrentDesktop: ubuntu:GNOME
Date: Tue May 25 14:25:12 2021
DefaultProfileExtensions: extensions.sqlite corrupt or missing
DefaultProfileIncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
DefaultProfileLocales: extensions.sqlite corrupt or missing
DefaultProfilePrefErrors: Unexpected character ',' before close parenthesis @ /usr/lib/firefox/omni.ja:greprefs.js:352
DefaultProfileThemes: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
InstallationDate: Installed on 2019-11-30 (542 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
IpRoute:
 default via 192.168.1.1 dev enp7s0 proto dhcp metric 100
 169.254.0.0/16 dev enp7s0 scope link metric 1000
 192.168.1.0/24 dev enp7s0 proto kernel scope link src 192.168.1.106 metric 100
Profile0Extensions: extensions.sqlite corrupt or missing
Profile0IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
Profile0Locales: extensions.sqlite corrupt or missing
Profile0PrefErrors: Unexpected character ',' before close parenthesis @ /usr/lib/firefox/omni.ja:greprefs.js:352
Profile0PrefSources: prefs.js
Profile0Themes: extensions.sqlite corrupt or missing
Profiles:
 Profile1 (Default) - LastVersion=None/None (Out of date)
 Profile0 - LastVersion=88.0.1/20210504152106 (In use)
RunningIncompatibleAddons: False
SourcePackage: firefox
UpgradeStatus: Upgraded to hirsute on 2021-03-24 (61 days ago)
dmi.bios.date: 07/18/2019
dmi.bios.release: 5.14
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P3.10
dmi.board.name: B450M-HDV R4.0
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP3.10:bd07/18/2019:br5.14:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnB450M-HDVR4.0:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.sku: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.

[Sebastien Bacher (seb128)]

Thank you for your bug report. Do you get any error printed on the command line if you start firefox from there? Could you try if it works with another webbrowser ?

[BertN45 (lammert-nijhof)]

I almost never use another browser, I use Chromium in a Xubuntu 20.04 Virtual Machine, but exclusively for WhatsApp Web. It is running constantly and I never had this problem, maybe because I never change that site.
I have Microsoft Edge in an Ubuntu 20.04 VM just out of curiosity, but I almost never use it.

The error occurs occasionally say once or twice per day and it happens in the middle of a session, not directly after start up. I will start up firefox from the terminal and look at error messages, when it occurs.

I don't think I ever had this problem in my VMs based on 20.04.

[BertN45 (lammert-nijhof)]

It happened again and it happened while I queued a number of video.

The messages displayed were:

Sandbox: attempt to open unexpected file /sys/devices/system/cpu/online
Sandbox: attempt to open unexpected file /proc/stat
Sandbox: attempt to open unexpected file /proc/net/unix
Sandbox: attempt to open unexpected file /proc/self/maps
Sandbox: attempt to open unexpected file /proc/net/unix

(firefox:1428435): GLib-GObject-WARNING **: 23:44:55.801: g_object_get_is_valid_property: object class 'GdkX11DeviceCore' has no property named 'device-id'

(firefox:1428435): GLib-GObject-WARNING **: 23:45:21.546: g_object_get_is_valid_property: object class 'GdkX11DeviceCore' has no property named 'device-id'