Can't route VLAN with UCOPIA

I'm writing to you because I can't solve a problem with a client.

My client has an infrastructure with the following characteristics:

2 ISP routers
1 fortigate firewall
1 dedicated router that broadcasts a UCOPIA US250 guest portal
65 Zyxel switches (1900 - 24) and one 4600 switch (4x 24 ports for the core network)
250 WIFI LIGOWAZE NFT terminals
80 VLANs

I do not manage the first 3 equipments, it is another provider.

Today, I have to pass the VLAN dedicated to the guests. The other provider has set up the FORTIGATE to broadcast the DHCP and the associated VLAN on the DMZ port to the OUT port of the UCOPIA. I have to broadcast VLAN 420 from the IN port to the ZYXEL switch and to the LIGOWAVE terminals.

However, when I am connected to the UCOPIA on the IN port, I manage to get the desired IP and to reach the portal, but when I test on the ZYXEL switch, it is impossible to get the dedicated VLAN. I put myself on another port of the ZYXEL, I TAG the VLAN in question. I have modified the ID of my VLAN on my computer in DHCP that does not work. I tried to use static IP but still nothing. I can't even ping the gateway. The ZYXEL port to which the UCOPIA is connected is TAGGED on the dedicated VLAN. I have also tried Untagged and excluding all the other VLANs but it is impossible to get this network.

Do you have any other ideas for me?

Here, you can see my diagram network: MyNetwork

Solution

I resolved my problem.

I configured Switch like that:

Untagged dedicated VLAN

But i forgot to change the PVID VLAN.

I changed it and that work !