~$ sudo rm /tmp/apt-key-gpghome.mOWm5D4pVJ/home:corrad1nho.asc.gpg
rm: cannot remove '/tmp/apt-key-gpghome.mOWm5D4pVJ/home:corrad1nho.asc.gpg': No such file or directory
nadeem14@Nadeem-Linux:~$ apt update
Hit:1 http://archive.ubuntu.com/ubuntu bionic InRelease
Hit:2 http://archive.canonical.com/ubuntu bionic InRelease
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:4 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Ign:5 http://packages.linuxmint.com tricia InRelease
Get:6 http://archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Hit:7 https://repo.windscribe.com/ubuntu zesty InRelease
Hit:8 http://download.opensuse.org/repositories/home:/corrad1nho/xUbuntu_18.04 InRelease
Hit:9 http://packages.linuxmint.com tricia Release
Get:10 http://security.ubuntu.com/ubuntu bionic-security/main amd64 DEP-11 Metadata [46.1 kB]
Err:8 http://download.opensuse.org/repositories/home:/corrad1nho/xUbuntu_18.04 InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B955BE41488C6624
Hit:11 http://download.opensuse.org/repositories/home:/kozec/xUbuntu_18.04 InRelease
Get:12 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages [983 kB]
Get:14 https://mega.nz/linux/MEGAsync/xUbuntu_18.04 ./ InRelease [2,468 B]
Get:15 http://security.ubuntu.com/ubuntu bionic-security/universe amd64 DEP-11 Metadata [49.1 kB]
Get:16 http://security.ubuntu.com/ubuntu bionic-security/multiverse amd64 DEP-11 Metadata [2,464 B]
Get:17 http://archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages [701 kB]
Get:18 http://archive.ubuntu.com/ubuntu bionic-updates/main Translation-en [333 kB]
Get:19 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 DEP-11 Metadata [294 kB]
Get:20 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages [1,086 kB]
Get:21 http://archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages [1,023 kB]
Get:22 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 DEP-11 Metadata [279 kB]
Get:23 http://archive.ubuntu.com/ubuntu bionic-updates/multiverse amd64 DEP-11 Metadata [2,468 B]
Get:24 http://archive.ubuntu.com/ubuntu bionic-backports/universe amd64 DEP-11 Metadata [7,972 B]
Fetched 5,062 kB in 25s (202 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
2 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://download.opensuse.org/repositories/home:/corrad1nho/xUbuntu_18.04 InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B955BE41488C6624
W: Failed to fetch http://download.opensuse.org/repositories/home:/corrad1nho/xUbuntu_18.04/InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B955BE41488C6624
W: Some index files failed to download. They have been ignored, or old ones used instead.
nadeem14@Nadeem-Linux:~$ wget -nv https://download.opensuse.org/repositories/home:corrad1nho/xUbuntu_18.04/Release.key -O /tmp/home:corrad1nho.asc
2020-07-01 23:05:43 URL:https://download.opensuse.org/repositories/home:/corrad1nho/xUbuntu_18.04/Release.key [1106/1106] -> "/tmp/home:corrad1nho.asc" [1]
nadeem14@Nadeem-Linux:~$ sudo apt-key add /tmp/home:corrad1nho.asc
gpg: invalid key resource URL '/tmp/apt-key-gpghome.QoNWqCZwq1/home:kozec.asc.gpg'
gpg: keyblock resource '(null)': General error
gpg: key B5B116B72D0F61F0: 13 signatures not checked due to missing keys
gpg: key D530E028F59EAE4D: 2 signatures not checked due to missing keys
gpg: key 3B57AE37123C1C64: 1 signature not checked due to a missing key
gpg: key A6616109451BBBF2: 12 signatures not checked due to missing keys
gpg: key 3B4FE6ACC0B21F32: 3 signatures not checked due to missing keys
gpg: key D94AA3F0EFE21092: 3 signatures not checked due to missing keys
gpg: key C8CAB6595FDFF622: 2 signatures not checked due to missing keys
gpg: key 871920D1991BC93C: 1 signature not checked due to a missing key
gpg: key B955BE41488C6624: 1 signature not checked due to a missing key
gpg: Total number processed: 12
gpg: skipped new keys: 12
Thank you so much!! it worked...i installed y ppa manger after that and imported all missing keys.. to sum it up , what was that magic command that fixed this up because i have the same problem on my laptop as well and i need to fix it..