I have just had a strange issue on my RB4011iGS-2HacQ2HnD, after about 80 days uptime on v6.48.8.
I noticed I cannot logon locally nor via VPN from the outside. It was returning the message that the router does not support secure connection, described here: http://forum.mikrotik.com/t/winbox-connection-error/137886/1
I had to force-reboot the router. Checking the logs afterwards showed this, repeating many times, for several of the DHCP pools:
dhcp,error WLAN-Guest_DHCP: failed to give out IP address: unknown pool
dhcp,error LAN_DHCP: failed to give out IP address: unknown pool
After the restart all seems to work ok again.
Has anyone else experienced the same problem?