Code
>sudo apt-key adv --no-tty --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0E98404D386FA1D9
Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).
Executing: /tmp/apt-key-gpghome.rxCKFLtYa1/gpg.1.sh --no-tty --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0E98404D386FA1D9
gpg: key 73A4F27B8DD47936: public key "Debian Archive Automatic Signing Key (11/bullseye) <ftpmaster@debian.org>" imported
gpg: Total number processed: 1
gpg: imported: 1
Code
Hit:11 http://packages.openmediavault.org/public shaitan InRelease
Err:10 http://httpredir.debian.org/debian bullseye-backports InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0E98404D386FA1D9 NO_PUBKEY 6ED0E7B82643E131
Fetched 92.3 kB in 2s (60.3 kB/s)
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://httpredir.debian.org/debian bullseye-backports InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0E98404D386FA1D9 NO_PUBKEY 6ED0E7B82643E131
W: Failed to fetch http://httpredir.debian.org/debian/dists/bullseye-backports/InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0E98404D386FA1D9 NO_PUBKEY 6ED0E7B82643E131
W: Some index files failed to download. They have been ignored, or old ones used instead.
Reading package lists... Done