RT AC88U Dual WAN with Fiber and Cable - How to set vlan id

[FraFis]

Hello, I want to configure Dual WAN on my Router.
On WAN I have a direct connection via cable modem as Primary WAN, WAN Connection Mode "Automatic IP", that works for a longer time.
Now I got a FTTH connection with a modem from the provider as second internet connection.
My Idea is to configure the new connection via "Dual Wan" as Secondary WAN - Ethernet LAN - LAN Port 4
Connection Type is PPPoE and I have to use the VLAN ID 7, but how can I configure the VLAN ID 7 on the port?
Via IPTV, Manual Setting the VID 7 on Port 4, I get this error message: "IPTV port number is the same as the Dual WAN LAN port number."

How can I configure that?

 

[Puschel]

I have the same problem.
I have two ISP
One is over is FTTH with dhcp without VLan
And two ist PPOE with VLan 7.
When i configure in IPTV section the Vlan, for one of Lan port i becane the same error message.
When i swwitch in IPTV setting Vlan for Internet.
The two complete dual Wan ist Vlan.
And i cant connect to FTTH.
Can me everyone Help.
I have an older acc66u there was it no problem, i switch in IPTV section to VLan on Lan Port 4 without error nessage and it runs.
Sorry for my bad english iam german