Snaps fail to load - Unable to init server

[Dustin Nisbet-Jones]

On Ubuntu 20.10, installed snaps fail to load with this error:

Unable to init server: Could not connect: Connection refused
Error: cannot open display: :0

The Snap of "joplin-james-carroll.joplin" gives this additional error:

(joplin:4653): Gtk-WARNING **: 17:44:10.729: cannot open display: :0
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu50.1
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 20.10
InstallationDate: Installed on 2020-07-15 (124 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
ProcVersionSignature: Ubuntu 5.8.0-29.31-generic 5.8.14
Snap: snapd 2.47.1 (latest/stable)
Tags: wayland-session groovy
Uname: Linux 5.8.0-29-generic x86_64
UpgradeStatus: Upgraded to groovy on 2020-11-10 (7 days ago)
UserGroups: adm cdrom dip lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True
modified.conffile..etc.sudoers.d.99-snapd.conf: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers.d/99-snapd.conf']

[Chris Guiver (guiverc)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1904485

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Dustin Nisbet-Jones (d.nisbetjones)]

apport information

[Dustin Nisbet-Jones (d.nisbetjones)]

apport information

[Dustin Nisbet-Jones (d.nisbetjones)]

apport information

[Dustin Nisbet-Jones (d.nisbetjones)]

I installed various Snaps to generate errors for this bug report:

Firefox:
Unable to init server: Could not connect: Connection refused
Error: cannot open display: :0

Todoist:
Failed to generate minidump.Segmentation fault (core dumped)

DOSBox-X
LOG: Early LOG Init complete
LOG: Logging init: beginning logging proper. This is the end of the early init logging
LOG: Logging: No logfile was given. All further logging will be discarded.
LOG: DOSBox-X version 0.83.7 (Linux SDL1)
LOG: E_Exit: Can't init SDL No available video device
E_Exit: Can't init SDL No available video device