I have been trying to set up an OPNSense router for quite some time now but each time I get a setup that seems to die some time after between 40minutes and 18 hours.
I have tried two different computers with three different NICs (all with different chipsets at speeds of 10G, 2.5G & 1G), different amounts of RAM, made up of different DIMMS, different storage media (m.2 nvme & sata ssd). I have tried with versions 25 & 26 of OPNSense.
Initially my network (no vlans or sub domains) was 192.168.0.0/16 but I have reconfigured it to 192.168.2.0/24 in case that was the problem.
I configure OPNSense with a single WAN ethernet connection to my fibre modem (with IP address provided by DHCP) and a single LAN connection to my network (with IP address 192.168.2.1). I make no further configuration changes whilst trying to get everything to work.
Each time, after an amount of time (between 40 minutes & 18 hours), the webGUI starts to break: Every "display section" of the dashboard will show "Failed to load widget" and the uptime will show something like 20000 days. Internet connectivity and DHCP services on my LAN do not seem to be affected. I can still SSH into the server and the system time remains accurate.
I don't know what else to try! How can I keep getting exactly the same fault on different hardware? Please, learned friends, give me the benefits of your experience and expertise!
"...and the uptime will show something like 20000 days"
System time fails? Results in all sorts of errors, as time is essential for many, many things on the interwebs. Check NTP. System board time? CMOS battery?
You are really alone with this kind of error...