Check if the pveproxy service is running: systemctl status pveproxy.service pvedaemon.service
Check if you can access the webUI from localhost: curl https://localhost:8006 -k | grep title
Check if the server is listening on port 8006: ss -tulpn
Check if the NIC uses a RTL8111/8411/8168 chipset: lspci | egrep -i --color 'network|ethernet'
If your host got multiple NIC check if your cable is plugged into the correct port. An ip addr
shouldn't show "NO-CARRIER" for that NIC.
Verify that your chosen IP isn't used twice (so no other machine already using it).
Verify that your chosen IP is outside of the DHCP IP range of your router.
In case you ever edited the network config, make sure you don't gave that PVE host multiple IPs that are part of the same subnet.
Try another ethernet cable in case that cable is broken.
Reboot your router and PVE server.
Check your routers/clients firewall rules.