I have EXACTLY the same problem! Everything that goes through the "main" IP address of the server won't connect after a few days, like SSH, the Unraid web UI and all SMB shares. Also all docker containers with bridge network mode (same IP as server) are offline. All other docker containers with an IP address of their own (network mode br0) are running perfectly and their web UI is reachable. So I can rule out a defect of the network card, since all docker containers with their own IP are reachable. I exchanged the USB flash drive yesterday, but today the web UI died on me again, so probably it wasn't the flash drive either. When I press the power button the server shuts down cleanly (I see the shutdown messages on the attached monitor), so the Unraid "core" seems to be still running when the connection problem occurs. After a reboot everything works fine for a few days or even one or two weeks. The server hardware is only about a 8 or 9 month old and ran perfectly for the first half year. The problem appeared roughly two or three month ago, I think some time after I installed 7.1.4. Next thing I'll try is to downgrade to 7.1.2 or another older version...