WG302v2 does not fit into VLAN

I have an old WG302v2 Access Point that I only use for testing.
I have to use it now with VLANs.
If I reset and use a normal unmanaged switch I can access and configure it.
If I plug it into a managed switch I can't even access it.
I tried both assigning its IP from a DHCP server and assigning a static IP.
I tried leaving VLAN1 untagged and management, but I also tried assigning untagged 1 and management 101.
Obviously the switch has the trunk and untagged ports assigned correctly.
I don't want to use VLAN1, while for management I would like to use 101.
If configured, then it should provide 4 SSIDs with VLANs 101,102,103 and 104.

Can anyone help me even if the model is very old?
The Firmware is updated to the latest version available.