Proxmox and cloudflared Tunnelling

That is a common mistake with proxmox on hetzner servers. You must not using a bridge to your public interfaces. You have to use a routet solution. Background: pve creates another virtial device (for firewalling) with random mac adresses for each host and put in the bridge too. So hetzner will detect more than the allowed mac adresses. I found no way to prevent this, it is the solution/design from pve. I had this problem too, tried different workarouds but have to switch to the routet solution. Everything is fine now. I did'nt found a way to prevent the creating of addition devices for each VM. If you MUST use a bridge, do not use pve, use a plain qemu ontop another distribution. You can check if you affected (in your bridged) setup by check the devices in your bridge (assume this is vmbr0) https://forum.proxmox.com/threads/mac-address-abuse-report.95656/post-446006