DHCP Server Error/dhcp failed. apipa is being used

Hi, currently using Packet tracer i am trying to configure my Router for a DHCP Server (It is an optional task but would like to understand how it works). *I am trying to assign 20 PC's with a IP Address between the range 175.200.0.225 - 175.200.0.254. *Whilst the network address is 175.200.0.224 and subnet of 255.255.255.224.

This is the config i am entering (Withing global config)

*int fa0/0 *ip address 175.200.0.225 255.255.255.224 *no shut *exit *ip dhcp pool Ip-Admin *network 175.200.0.224 225.255.255.224 *defult-route 175.200.0.255 *ip dhcp exclude 175.200.0.255 175.200.0.254 Whenever i try to check the DHCP ip address of the 3 connect PCs (I will be adding more) it says 'dhcp failed. apipa is being used' Anybody know why? or what i am not doing correctly? 

This is the first thing i have been trying to config for a few hours and worked with an other example. (The formatting is not working so apologies for the mess)