I'm trying to install some software via flatpak and have attempted to add "Flathub" as a remote source for said software but it seems to fail on the key signing portion.
This is on Ubuntu 20.04 under release 1.6.5, through package manager. I have removed and purged flatpak, reinstalled, and tried again to no avail.
flatpak remote-add --if-not-exists flathub https://flathub.org
/repo/flathub.flatpakrepo
error: Signature made Wed 31 Dec 1969 07:00:00 PM EST using [unknown name] key ID 562702E9E3ED7EE8
BAD signature from "Flathub Repo Signing Key <flathub@flathub.org>"
Primary key ID 4184DD4D907A7CAE
Primary key expires Mon 14 Jun 2027 09:18:56 AM EDT
Alright I was able to figure out a way around this, don't use the release for flathub for Ubuntu 20.04. Unfortunately this release of Ubuntu has been quite problematic from improperly configured libs for Steam, etc.
Simply put, follow https://flatpak.org/setup/Ubuntu which will have you add their stable release repository and install that over what Ubuntu 20.04 provides.