I have 5 nodes in my network. Running in Access Point mode with my ISP router providing IP addresses with 199 available in the range. Wifi is disabled on the router. The main node and 2 others are connected to the router via ethernet. The other 2 nodes connect to the main node over wifi. This set-up has run well for 5 yrs.

Whilst on holiday I enabled ECO mode, reduced power to ultra power saving and scheduled an overnight shut down of wifi. Whilst away the router moved to a static IP address.On my return I turned ECO mode off.

Initially no devices could connect to the wifi as they couldn't obtain an ip address. I power cycled them all to no effect then a firmware update partially resolved this.

The 3 nodes connected by ethernet now provide a wifi network for most of the house that devices can connect to and seamlessly roam from node to node. However the 2 nodes that connect over wifi will not connect to other nodes. 

I have re-set and added them again. The app reports a successful add, the node appears in the list but Offline, I can see in available Wifi networks a new wifi network Deco_aaaa, and the Led is solid blue. After 20+mins I power cycle the node and the Led initially flashes orange then goes solid red, the Deco_aaaa wifi network disappears. If I plug an ethernet cable in the node joins the mesh network. This isn't unique to 1 node, I have swopped various nodes around, they all work on ethernet, none will connect over wifi.

The settings are:

Wifi / Advanced Security WPA2, Band 2.4ghz and 5ghz enabled

Guest network disabled

IoT disabled

No blocked devices

Network Optimization shows no interference

Internet speed is as expected

Advanced - Operation Mode Access Point, Smart DHCP disabled, Fast roaming Enabled, Beamforming Enabled

All Deco's are on the latest firmware; 1.9.1 Build 20250909 Rel 37570 

Supports solution was to buy a new system as it's 5 yrs old. A single node suffering a hardware failure after 5 yrs would be disappointing but it could be a valid solution. I don't accept all 5 nodes have suffered the same failure at the same time. 

Anybody got any suggestions?