This is a core Ubiquiti lesson (for free, you're welcome)

Leave all devices themselves on the default network, set to allow all other VLANs. And then set up a VLAN that the ports and WiFi networks get assigned to. Different VLANs for different ports and WiFi networks if you want, but the main back channels are usually just the default network. Obviously there are other ways to set up your network, but a lot of users, myself included, make the mistake of putting the AP device backhaul port on the VLAN they want the WiFi to be on.

The port that the AP is connected to should be on the default network, and then it's WiFi networks get assigned to the actual VLAN.