Unable to Connect to SSID and Receive IP Address on WAP

Hi Guys,

I work with three Cisco switch stacks which relate to 3 floors in our building. They are linked via IP port channels so each floor is essentially their own network.

I have created a Guest VLAN (240) on our new WiFi infrastructure. This Vlan interface has been created on the 3rd floor switch and then added on the other two. I want the guest VLAN to be available on all three floors as one network. I have therefore extended the Vlans across the three switches via trunks allowing the 240 vlan.

I have connected a WAP on the 3rd floor switch and I have able to get a 240 IP from from our SonicWall and connect to the guest network. However when I connect a WAP to the 1st floor and try to connect to the guest network I can not get an IP. I tried on my mobile device and it is stuck on obtaining IP.

Any ideas where I should be looking to try to resolve this? Thanks.