It would seem highly unlikley to me that both minix devices would fail at the same time to connect assuming they have been working previously.
I would check all cables, switches and reboot both router and minix and power off / on all devices in the LAN chain.
Check router settings to make sure they are on the same LAN subnet, and if on wifi make sure antennas are firmly attached .
IN minix settings select only wifi or ethernet, never have both on.
Think back to what you may have done / changed since they last worked.