If it is Ubuntu, it needs apparmor profile as described on Launchpad bug if Itch sandbox issue is still not solved or Ubuntu settings changed. But Itch has not this apparmor setting established yet.
Still –no-sandbox added to .local/share/applications and also to .config/autostart could also solve this,
or could use itch setting with not to use sandbox but this setting don’t work
or something not so standard required like firejail, but this seems strange…
if on Chomebook, something Google strange could happens…