DHCP HELP!

Hi all
I got MT 2.9.6. He is NAT and DHCP server. I got 2 interfaces
LAN (192.168.0.)
WAN (82.
..)

When my ISP change form fixip to Dhcp adress i got problems, my router block after 30 mins. When i click on release he works. I have Mt 2.9.2 before 2.9.6 and hi got same problems.
Any ideas?

Please post your configuration… and tell us more about your problem so we can help…