Запуск sudo apt update и показывает ошибки

I я работаю 21.04 Когда я запускаю обновление, он показывает несколько ошибок. Как их исправить? или их следует игнорировать? Спасибо, Клифф

, результаты apt update

Ign:9 http://linux.dropbox.com/ubuntu eoan InRelease      
Err:10 http://linux.dropbox.com/ubuntu eoan Release
  404  Not Found [IP: 13.227.39.129 80]
Err:8 http://archive.canonical.com/ubuntu bionic InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32
Reading package lists... Done
E: The repository 'http://linux.dropbox.com/ubuntu eoan Release' does not have a Release file.
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 bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32
E: The repository 'http://archive.canonical.com/ubuntu bionic 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.