Why Can T My Android Connect To My Mac Pro S Wireless Hotspot

I have been trying to use my office’s Mac Pro network by creating a wireless hotspot for my Android device. I went through the whole procedure, created a network with 40bit encryption and a 5-letter password but when I tried to connect from my Android device the connection failed as it was unable to obtain an IP address.

What am I doing wrong? Is there anything I need to know about creating a hotspot in Mac OS X 10.7.5? I am using Android Jelly Bean (4.2).