mensagem:

You do not have a valid subscription for this server. Please visit www.proxmox.com to get a list of available options.

para remover a mensagem:
sed -i "s/getNoSubKeyHtml:/getNoSubKeyHtml_:/" /usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.js && systemctl restart pveproxy.service && reboot
https://www.init-d.ru/2018/03/21/proxmox-message/

https://pve.proxmox.com/wiki/Install_Proxmox_VE_on_Debian_Buster
https://www.servethehome.com/proxmox-ve-6-initial-installation-checklis…