OpenWrt 21.02.3
PC connected to router with LAN.
After PC Reboot or disabling and re-enabling connecting in Windows settings - PC can't connect to router with "Unidentified Network" error. It fixes when physically unplug and plug cable again.
Tried to set static lease to PC, don't work, still have error after reboot.
Do you have another computer to try? This sounds like it is a Windows problem (maybe specific to that PC), but the only way to know for sure is to try another computer.