Weird issue last night , my UDM base - which is now coming up to 5 years old, threw a wobbly one.
The Unifi controller wouldn't show the status of the ports, so I went into the console and issued a reboot command to try to clear the issue. It rebooted fine but couldn't connect to my fibre ONT when it rebooted.
I reset the UDM and installed a backup from the Cloud from the 7th of June, the UDM installed the backup but still couldn't connect to the ONT and said my ISP was down. I quickly rigged up my Mikrotik 5009 with a basic config and it connected to the ONT via PPPOE with no issues. So I plugged my 8-150 switch and wifi access points into the 5009 so my wife would have a working connection for work today - all worked fine with no issues.
So tonight, I have factory reset the UDM and loaded the latest backup and rebooted. Again the UDM couldn't connect to the ONT and said my ISP was down. So did a factory reset again, slapped a new config on the UDM, reset the switch, access points and adopted them in to the new unifi config - everything worked with zero issues. UDM appears to be happy, no errors in the controller log.
I will have to keep an eye on the UDM, never had any issues at all with it during the past 5 years, might have to think about getting one of those new UCG Ultras sooner than later.