I have the ports on me switches configured as trunks and added a helper-address VLAN but now the IAP is offline.
Below is an example of what I have from Central with the configuration of the wired port connection from IAP to Switch.
Access Point Ports
Networks > Configuration - default_wired_port_profile
Mode: Trunk
Client IP Assignment: External DHCP server assigned
Native VLAN: 130
Allow VLAN: 250,260
Is that configuration correct?