PROX400 - Invalid Response From Proxmox

Agent error code #PROX400 indicates that the agent received a response from Proxmox VE that it could not parse as the expected ipset data. The request reached Proxmox, but the body was not in the form the agent expected.

Common causes include:

• The backend URL points at something other than the Proxmox VE API (for example a reverse proxy or a different web service on the same host)
• A proxy or middlebox rewrote or wrapped the API response
• An incompatible or unexpected Proxmox VE version returned a different response shape

Steps to Resolve

Confirm the URL Points at the Proxmox API

1. In the Knocknoc admin interface, open the backend configuration for the affected Proxmox Knoc
2. Confirm the Hostname points directly at the Proxmox VE API root, e.g. https://pve.example.com:8006
3. Confirm no reverse proxy in front of Proxmox is altering API responses

Review the Agent Logs

The agent log records the raw response that failed to parse. Review it to confirm whether the endpoint is genuinely the Proxmox API.

For more details, see the Proxmox setup guide.

Still Having Issues?

We can help you out, contact us at [email protected].