I got this issue while running apt update command :
Err:12 http://us.archive.ubuntu.com/ubuntu precise-security InRelease
The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
Get:15 http://us.archive.ubuntu.com/ubuntu precise-updates InRelease [55.7 kB]
Err:15 http://us.archive.ubuntu.com/ubuntu precise-updates InRelease
The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
Get:21 http://us.archive.ubuntu.com/ubuntu precise-backports InRelease [55.7 kB]
Err:21 http://us.archive.ubuntu.com/ubuntu precise-backports InRelease
The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
Get:27 http://us.archive.ubuntu.com/ubuntu precise Release.gpg [198 B]
Ign:27 http://us.archive.ubuntu.com/ubuntu precise Release.gpg
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: https://dl.yarnpkg.com/debian stable InRelease: The following signatures were invalid: EXPKEYSIG 23E7166788B63E1E Yarn Packaging <yarn@dan.cx>
W: GPG error: http://extras.ubuntu.com/ubuntu precise Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192
E: The repository 'http://extras.ubuntu.com/ubuntu precise Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://archive.canonical.com/ubuntu precise Release: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository 'http://archive.canonical.com/ubuntu precise Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://us.archive.ubuntu.com/ubuntu precise-security InRelease: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository 'http://us.archive.ubuntu.com/ubuntu precise-security InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://us.archive.ubuntu.com/ubuntu precise-updates InRelease: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository 'http://us.archive.ubuntu.com/ubuntu precise-updates InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://us.archive.ubuntu.com/ubuntu precise-backports InRelease: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository 'http://us.archive.ubuntu.com/ubuntu precise-backports InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://us.archive.ubuntu.com/ubuntu precise Release: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository 'http://us.archive.ubuntu.com/ubuntu precise Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
I have run some commands to fix another issue after that I don't know which file has been deleted and this update issue occurred. Please help me to solve this problem
