The ZD port should be configured as an Access port and the APs uplink port as a trunk port and try to ping the AP IP from the ZD. We need to configure the AP uplink port that connects to the switch as a Trunk port to forward all the traffic. We need to check if there is any management VLAN ID configured on the ZD GUI: ZD GUI >> configure >> Access Points >> Access point policies >> Management VLAN.
If a DHCP server is configured in the network then the AP would be assigned an IP address even if it is not connected to the ZD.
VLAN 1 is always a Native untagged VLAN in Ruckus. When an AP is connected to a switch port for example the switch would have Native VLAN 1 by default and we allow certain VLANs as tagged based on our requirement. So, if we consider the Switch port is having Native VLAN1 and SSID is configured with VLAN1 when a client connects to the SSID since VLAN 1 is mentioned in WLAN it would request an IP with untagged and it will reach switch port where that AP is connected. Since Native VLAN is 1 and it would get an IP from that default VLAN scope. However, when we configure VLAN no. 20 other than 1 in WLAN the request will go as tagged to the switch port where AP is connected and the switch port should allow VLAN 20 as tagged.
If you have further queries, please open a service request and I will be glad to assist you over a remote session.