Post kernel 6.8.12-8, bug was introduced which causes the NIC to crash and not recover. Revert to 6.8.12-8 kernel to prevent the problem. Other temporary solutions include turning off cpu-offloading options. In the Node console:
apt updateapt install proxmox-kernel-6.8.12-8-pveproxmox-boot-tool kernel pin 6.8.12-8-pve
*Update* This bug still exists in Promxox 9.2.11 (kernel 7.0.14-14).
This proxmox thread is following the issue as well as possible solutions. https://forum.proxmox.com/threads/proxmox-6-8-12-9-pve-kernel-has-introduced-a-problem-with-e1000e-driver-and-network-connection-lost-after-some-hours.164439/page-9