yes, MAC address is perfect.
Then you have a problem outside the MikroTik router. All the dhcp stuff shows that device is being issued 192.168.2.3 by that router.
Are you sure the router is the only dhcp server on that network? You might want to look into "/ip dhcp-server alert".
http://wiki.mikrotik.com/wiki/Manual:IP ... ver#Alerts
edit: If you did not find another dhcp server on the network, then you might want to set verbose logging for the dhcp server, then renew the lease on your device and check the log.
add topics=dhcp,debug action=memory
If you have any questions, post the log entries.