I have looked at the troubleshooting area on the controller for my test client and I noticed the difference between a good complete connection from the R720 and the T750. The R720 provided DHCP offering form the DHCP server and the T750 did not so it never gets the DHCP address.
Any help is appreciated. I'm thinking is there anything special about the T750 that needs another option configured on the DHCP server? option 43 is already there and as I said everything works fine with R720 but I just bought these T750 for an outdoor event.