Lan Device have to connect manually after reboot

I using mi 4c router ...i have 2 ethernet ports....i have 4 devices...they connected via unmanaged switch.after every reboot ethernet connection lost of the unmanaged switch..if i connect cable 2 time in router lan port....the port shart blinking..and all device get internet.i need solution for this problem.every time connecting and disconnecting is painful.

I suspect the switch does not transfer the "link down" info to the client PC. Perhaps a static lease for the clients will help.

not worked