Interesting that you mentioned "all untagged". Are you set to use VLANs but only have the default or are you set to not use VLANs?  Almost every time I have seen the issue you describe it is because the data is getting double tagged.  In this case, if you set the SSID to tag the default VLAN and the switch port was untagged on the same VLAN the you would be double tagging and the DHCP server would never see the DHCP request on a valid VLAN.   If you are setting a VLAN in the SSID, try turning that off and see if you start picking up DHCP addresses on your clients. ... View more