My proxmox box which runs on an Intel NUC started crashing regularly out of the blue. I looked at the log files in /var/log (specifically the syslog) and found an error reading:

e1000e 0000:00:1f.6 eno1: Detected Hardware Unit Hang

Looking around on the Proxmox forums I (of course) was able to find the answer to the problem.

Running the following two commands below solved my regular crashes.

post-up ethtool -K eno1 tso off
post-up ethtool -K vmbr0 tso off

So far so good!