1、删除企业源
vim /etc/apt/sources.list.d/pve-enterprise.list
//注释掉
#deb https://enterprise.proxmox.com/debian/pve stretch pve-enterprise
//也可以直接删除
rm -f /etc/apt/sources.list.d/pve-enterprise.list
2、添加免费源
echo “deb http://download.proxmox.com/debian/pve stretch pve-no-subscription” > /etc/apt/sources.list.d/pve-install-repo.list
echo ‘deb http://download.proxmox.com/debian/pve buster pve-no-subscription’ >> /etc/apt/sources.list.d/pve-no-subscription.list
apt update
apt upgrade