NO_PUBKEY error of apt update

I'm trying to perform apt-update on ubuntu 22.04 LTS and I get an error

root@kisharra:~# apt updateHit:1 http://apt.postgresql.org/pub/repos/apt jammy-pgdg InReleaseHit:2 http://ru.archive.ubuntu.com/ubuntu jammy InReleaseGet:3 http://ru.archive.ubuntu.com/ubuntu jammy-updates InRelease [119 kB]Get:4 http://security.ubuntu.com/ubuntu jammy-security InRelease [110 kB]Err:2 http://ru.archive.ubuntu.com/ubuntu jammy InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CHit:5 http://ru.archive.ubuntu.com/ubuntu jammy-backports InReleaseErr:3 http://ru.archive.ubuntu.com/ubuntu jammy-updates InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CErr:5 http://ru.archive.ubuntu.com/ubuntu jammy-backports InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CErr:4 http://security.ubuntu.com/ubuntu jammy-security InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CFetched 229 kB in 2s (140 kB/s)Reading package lists... DoneBuilding dependency tree... DoneReading state information... Done2 packages can be upgraded. Run 'apt list --upgradable' to see them.W: http://apt.postgresql.org/pub/repos/apt/dists/jammy-pgdg/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://ru.archive.ubuntu.com/ubuntu jammy InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://ru.archive.ubuntu.com/ubuntu jammy-updates InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://ru.archive.ubuntu.com/ubuntu jammy-backports InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://security.ubuntu.com/ubuntu jammy-security InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: Failed to fetch http://ru.archive.ubuntu.com/ubuntu/dists/jammy/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: Failed to fetch http://ru.archive.ubuntu.com/ubuntu/dists/jammy-updates/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: Failed to fetch http://ru.archive.ubuntu.com/ubuntu/dists/jammy-backports/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: Failed to fetch http://security.ubuntu.com/ubuntu/dists/jammy-security/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93CW: Some index files failed to download. They have been ignored, or old ones used instead.

As you can see, 4 packages were not updated due to the lack of PUBKEY 871920D1991BC93C but if you look at the output of the apt-key list command, it is there

root@kisharra:~# apt-key listWarning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8))./etc/apt/trusted.gpg--------------------pub   rsa4096 2012-05-11 [SC]      790B C727 7767 219C 42C8  6F93 3B4F E6AC C0B2 1F32uid           [ unknown] Ubuntu Archive Automatic Signing Key (2012) <ftpmaster@ubuntu.com>pub   rsa4096 2011-10-13 [SC]      B97B 0AFC AA1A 47F0 44F2  44A0 7FCC 7D46 ACCC 4CF8uid           [ unknown] PostgreSQL Debian Repository/etc/apt/trusted.gpg.d/ubuntu-keyring-2012-cdimage.gpg------------------------------------------------------pub   rsa4096 2012-05-11 [SC]      8439 38DF 228D 22F7 B374  2BC0 D94A A3F0 EFE2 1092uid           [ unknown] Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>/etc/apt/trusted.gpg.d/ubuntu-keyring-2018-archive.gpg------------------------------------------------------pub   rsa4096 2018-09-17 [SC]      F6EC B376 2474 EDA9 D21B  7022 8719 20D1 991B C93Cuid           [ unknown] Ubuntu Archive Automatic Signing Key (2018) <ftpmaster@ubuntu.com>/etc/apt/trusted.gpg.d/ubuntu.lafibre.info.gpg----------------------------------------------pub   rsa4096 2018-09-17 [SC]      F6EC B376 2474 EDA9 D21B  7022 8719 20D1 991B C93C                                     ^^^^^^^^^^^^^^^^^^^uid           [ unknown] Ubuntu Archive Automatic Signing Key (2018) <ftpmaster@ubuntu.com>

this command outputs the following

root@kisharra:~# apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 871920D1991BC93CWarning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).Executing: /tmp/apt-key-gpghome.LfbmJQ2SFz/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys 871920D1991BC93Cgpg: key 871920D1991BC93C: "Ubuntu Archive Automatic Signing Key (2018) <ftpmaster@ubuntu.com>" not changedgpg: Total number processed: 1gpg:              unchanged: 1

after using this command

root@kisharra:~# gpg --export --armor 871920D1991BC93C | sudo apt-key add -Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).OK

tried to update the packages again and same error, if anyone has any ideas, please help