Ubuntu 18 sudo apt-get update not working, how to fix?

Question

linux

Ubuntu 18, sudo apt-get update fails, how to fix?

[email protected]:~# sudo apt-get update
Hit:1 http://mirror.yandex.ru/ubuntu bionic InRelease
Hit:2 http://mirror.yandex.ru/ubuntu bionic-updates InRelease                                 
Hit:3 http://mirror.yandex.ru/ubuntu bionic-backports InRelease                               
Hit:4 http://security.ubuntu.com/ubuntu bionic-security InRelease                             
Hit:5 http://download.ispsystem.com/repo/ubuntu base-bionic InRelease                         
Hit:6 http://download.ispsystem.com/repo/ubuntu 5.259-bionic InRelease                        
Get:7 https://repo.cloudlinux.com/kernelcare-debian/6 stable InRelease [1,857 B]  
Err:7 https://repo.cloudlinux.com/kernelcare-debian/6 stable InRelease
  The following signatures were invalid: E58FE9B3FE3B0470525159BD6DC3D600CDEF74BB
Reading package lists... Done
W: GPG error: https://repo.cloudlinux.com/kernelcare-debian/6 stable InRelease: The following signatures were invalid: E58FE9B3FE3B0470525159BD6DC3D600CDEF74BB
E: The repository 'http://repo.cloudlinux.com/kernelcare-debian/6 stable 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.

Answer 1

My subscription to cloudlinux.com/kernelcare has expired. SO either renew the subscription or remove the repository from the apt source list

Answer 2

repository keys do not match
here read how to fix
it there is a link to generate a new Ubuntu Sources List Generator list