Hi there, I'm having issues getting a Deco M5 guest network working correctly.

The network topology is very simple, as follows. Deco #1 was set up first, in router mode, then Decos #2 and #3 were added. Backhaul is wired and through a TP-Link un-managed switch.

The main wifi network works without any issues across all 3 Deco M5 units. All is well so far!

The problem is with the guest network. The guest network was created from within the Deco app without any issues.

When connecting to the guest network from a physical location next to Deco #1, wifi connects and has internet access with no issues.

However, when trying to connect to the guest network from a physical location next to Deco #2 or Deco #3, wireless devices will either connect but have no internet connectivity, or fail to connect with a 'can't obtain IP address' error.

It appears that something is going wrong with the setup of the guest network that is preventing remote clients from seeing Deco #1 (which is the unit that hands out IP addresses and does DNS resolution).

My expectation is that the guest wifi network has the same coverage as the main wifi network (i.e. the whole network).

Troubleshooting steps already attempted:

• Update all units to latest firmware (done, no change)
• Remove Deco #2 and #3 (guest network is visible and accessible from Deco #1 and works with no issues)
• Remove all units, factory reset them all, then re-add one by one (no change)
• Tried connecting from multiple different devices (laptops and phones) (no change)

I can't understand why the guest wifi network is visible but isn't useable from the 'remote' Deco units.

Questions

1. In the configuration drawn above, should the guest network be visible and usable from the 'remote' Deco units #2 and #3? I assume the answer has to be yes (or the product is fundamentally flawed).
2. What should I try next?

Thanks in advance. These units are marketed and sold as being simple to connect and configure, but this issue has me stumped...