apt-getアップデートに失敗しました

sudo apt-get updateKali仮想マシンで実行しようとすると、次のメッセージが表示されました。なぜですか？

root@kali:~# sudo apt-get update
Get:1 http://http.kali.org/kali kali-rolling InRelease [3,415 B]
Err:1 http://http.kali.org/kali kali-rolling InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Reading package lists... Done       
E: Failed to fetch http://http.kali.org/kali/dists/kali-rolling/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://http.kali.org/kali kali-rolling InRelease' is no longer 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.
root@kali:~#

# cat /etc/resolv.conf
# Generated by NetworkManager
search *omitted*.com
nameserver 192.168.10.240
nameserver 192.168.32.215