Hi and thank you:-)

This is a very simple network. I have chosen just a class C network and thats all. My ISP provider has given me a "bridge mode" fiber box. 

I also have a Microsoft AD domain controller (primary domain). This has a DNS server and DHCP server. The server uses the address 192.168.1.6. My main deco uses 192.168.1.1. The DECO DHCP and Windows (AD controller) DHCP server uses different ip ranges when assigning addresses.

All subnetmask consist of "255.255.255.0" I have checked and rechecked all settings. 

I cannot reproduce every time. It happens maybe five times a year. 

To fix after a problem:

Disconnect Main DECO from the C network.

Restart Main DECO

Start Deco APP. Change LAN IP back to what I had before the crash.

Restart Main DECO and at the same time reattach to my class C network.

Restart all DECO satelites

Now it works again after some minutes.

  @OHO 

1. he default gateway IP address (e.g., 192.168.1.1 or 192 l.168.0.1) into your web browser. Make sure that the LAN IP address is set to the desired value (e.g., 192.168.1.1).

2. Reset your DECO router: If you can't access the router's administration panel or the settings seem incorrect, you can perform a factory reset on your DECO router. This will restore it to its default settings, including the default LAN IP address. Refer to your DECO router's manual or manufacturer's website for instructions on how to perform a factory reset.

3. Verify your ISP settings: If your ISP (Internet Service Provider) is causing issues or changing your network settings, it's important to contact them and inquire about the situation. They should be able to provide you with the correct configuration settings for your network.

4. Use a UPS (Uninterruptible Power Supply): If power outages are causing the LAN IP address to change, using a UPS can help keep your router and other network equipment powered during such situations. This will help maintain network stability and prevent unexpected changes in settings.

5. Copyrights:  https://19216811.how/

  @OHO 

I do recall I saw forum topic where it were discussed that Deco might change its IP settings when it is configured in 192.168.[0-5].* IP ranges. I can't find original forum topic where it were discussed, so it's from my memory.

The solution (workaround), I recall, was not to set Deco LAN in that IP range. Unless TP-Link Support replies here with different recommendation, I would suggest to change your Deco LAN IP range to 192.168.10.*