can the AP send VLAN 1 untagged? if not you are correct, you may need to make another VLAN you can send tagged frames to, for instance VLAN 3. And not use VLAN 1.
Current setup: Firewall and route point for two networks (staff and guest).  One port (port 1) is for the staff and a separate port (port 2) is for the guest.    Port 1 (staff) on the FW goes to a Dell connect 2724 with a managed default config.   All staff resources are on the dell connect.  Also on the dell connect is a wireless access point for the staff.  Port 2 (guest) plugs directly to a guest wifi  AP (separate from the staff).  Everything works. To be state: The wireless AP we use is the Engenius EAP350 and it has the ability to have 8 SSIDs each in their own VLAN.  I am looking to move both wireless networks onto a single AP.     To do this I moved the FW port 2 to a port on the dell connect (port 9) and put this in PVID 2 and changed the dell connect port that connected to the existing staff wifi AP (port 7) to a trunk port (tag 2).  all other settings are still default.  The staff wifi is vlan 1 and the guest wifi is vlan 2 and tagged on the AP.  My assumption is that the vlans are tagged at the AP, allowed through the dell connect trunk port port and then DHCP requests for vlan one then go to the FW through port one and dhcp requests for vlan 2 go to the fw on port 9.  It didn't work.  So to remove the AP from the equation all together, I made port 10 on the dell connect a PVID in vlan 2 also and plugged my laptop in it.  Since port 9 and 10 are both access ports in vlan 2, all dhcp requests should have been fullfilled by the FW in the correct subnet.  However, it did not work.  any ideas or examples that can be sent on access and trunk setup.  I am very well versed on them with cisco, but dell connects are doing it a little different.
VLANs not working as expected