Posted 21 March 2012 - 05:54 PM
First thing would be you should not connect a DHCP server directly to a dedicated modem from your ISP. You will probably get an error like this because you are conflicting with a server on their network. You will need to use a router to seperate the two distinct networks from one another.
Second possibility is that you are using a router currently and you did not turn off the DHCP server on the router.
Third possibility is that the server is a Static IP (which it should be) and the DHCP scope you setup also contains this IP address in the range of the scope. You should either rework the scope to not include this IP address or add an exclusion to the DHCP scope so it will not get assigned by the DHCP server.
Get your facts first, then you can distort them as you please.