Home Assistant Matter Hub Addon - Devices are showing offline in Google Home

[livid iron]

Helping out my brother setup the Matter Hub addon for this HA devices to appear and be controlled from the Google Home app.
Here is the addon I'm using: Home Assistant Matter Hub by t0bst4r --> https://github.com/t0bst4r/home-assistant-addons
We have successfully added the device(s) to Google Home app (by scanning the QR Code) -- Google home see's all those Home Assistant devices but they are offline.
Initially IPV6 was disabled from Home Assistant, so I enabled that -- still no luck.
We are using Unifi Network (UDM Pro, with the latest version of Network app) with multiple VLANs.
We have an IoT_Server VLAN (where Home assistant is) and IoT_Trusted (where the Google home speaker devices are).
Using zone based firewall -- I made sure that 5540 and 5541 allow to talk to each VLAN (mDNS and IGMP Snooping enabled).
Trying to figure whey it is still offline in Google Home and the only thing I noticed is that my ISP doesn't give me an IPv6 address.
All my VLANs do not have local IPv6 enabled and I don't have a prefix to use since my ISP doesn't give me one.
Is it required for the Matter Hub addon for the IPv6 to be enabled on the router level?
If yes, what do you typically use for Prefix and where can I get it -- if my ISP doesn't give me one.

[unique fulcrum]

Matter is not designed to cross vlans. Third party cross vlan mDNS reflector widgets is just asking for huge problems. It’s designed for basic flat consumer networks. Everything matter needs to be on the same vlan. Ubiquiti products also have a spotty history with breaking matter. Don’t know the current firmware stability as I use different brands.

Matter does not need ipv6 addresses from your ISP.

[livid iron]

ok thanks. Do you know if at least need to enable the ipv6 on the local VLAN (not the ISP)?

[round rapids]

shouldn't need to, but check the mdns responses to see whether they return an ipv6 address, ipv4 address, or both.

without an ipv6 prefix enabled on the network, it might end up using ipv6 link-local addresses, which can't be routed between vlans.

anyways, the recommended solution is just… put the matter devices (home assistant matter hub add-on is a bridge that acts as a matter device) and the matter controller (google device that works as a google home hub) on the same vlan.

[livid iron]

Yup thanks .. gonna move my IoT_servers to IoT_Trusted .. I should have known no to do that when I redid my network .. smh