Purchasing a subscription from Proxmox is certainly recommended if you’re planning to use it in anger or in a production environment as it will give you access to support, the enterprise repository and keep the developers supported.

But for a test environment, you can remove the message by simply editing one of the JavaScript files on the server.

This file does get overwritten when you update, so you will need to reapply when that happens.

Detailed Approach

cd /usr/share/javascript/proxmox-widget-tookit
cp proxmoxlib.js proxmoxlib.js.old
vi proxmoxlib.js

Search for Active until you find it in the following line:

if (data.status !== 'Active') {

And change it to:

if (false) {

Save the file and exit. Now restart the service to load the updated file:

systemctl restart pveproxy.service

One Liner Approach

sed -i.bak "s/data.status !== 'Active'/false/g" /usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.js && systemctl restart pveproxy.service

Even if you are feeling brave, I would recommend that you take a backup of proxmoxlib.js file before running the above command, just to be safe.