@ARGamingPK1 

Okay, I understand that after you started using Ethernet backhaul on one of your satellite Deco Mesh units, you experienced IP conflict issues, loss of Internet connection, and all devices were stuck on 'obtaining IP address'. Even the Deco app showed no Internet connection, and you could not manage the system. Previously, everything worked fine on wireless backhaul, but you switched to Ethernet because the satellite unit was not getting a strong signal.

Here are some troubleshooting steps to help resolve Ethernet backhaul issues and prevent IP conflicts:

1. Check IPTV/VLAN Settings:
Go to the Deco app > MORE > Advanced > IPTV/VLAN. If IPTV is enabled, the IPTV port cannot be used for Ethernet backhaul. Make sure you are not using the IPTV port for connecting your satellite Deco.

2. Try Different Ports and Cables:
Connect the satellite Deco to a different port on the main Deco or switch, and use a different Ethernet cable to rule out hardware issues.

3. Test Direct Connection:
If you are using a switch between Deco units, try connecting the two Decos directly with an Ethernet cable. If this works, your switch may be causing the issue.

4. Check Switch Loop Detection:
When a Deco switches from wireless to Ethernet, a brief network loop (1-2 seconds) can occur. If your switch has loop detection, it may block the port connected to Deco. Turn off loop detection on your switch, reboot the switch, and try again. If unsure, contact your switch manufacturer to confirm if loop detection is enabled by default or if there are hardware problems.

5. D-Link Switch Compatibility:
Several D-Link switches are not compatible with Deco's Ethernet backhaul (IEEE 1905.1 protocol). If you are using a D-Link switch, try replacing it with a different brand.

If you continue to experience IP conflicts or loss of Internet, please contact TP-Link support with the results of these troubleshooting steps for further assistance.

Note: Since you are using Router Mode, ensure that only one device in your network is acting as the DHCP server (usually the main Deco), and that your modem/router is set to bridge mode if possible to avoid double NAT or IP conflicts.

  @HelpFixDecoApp Thanks for your help...I'm waiting for the reply of @David-TP 

  @ARGamingPK1 

No worries :) 

  @ARGamingPK1 

Hi, nice to see you again.

Can I have the model number of the network switch?

Did Deco M4 also turn red/flashing red when all devices were stuck on receiving IP addresses from Deco?

If possible, could you please help me run a simple test:

• Unplugging the network switch and connecting one of the satellite M4s via an Ethernet cable directly to the main Deco M4.

Would the same issue keep happening?

Wait for your reply.

Best regards.

  @David-TP This is my ethernet switch/splitter and idk about model number. Yes all the Deco start flashing red. 

  @David-TP What can i do now?

  @ARGamingPK1 

Ok my curiosity got the best of me sorry. Why are you using a splitter and not a switch? An Ethernet switch connects multiple devices and manages network traffic, providing dedicated bandwidth and high speeds. An Ethernet splitter uses a single cable to create two separate connections, but this halves the bandwidth and limits speeds to \(100\) Mbps, making it suitable only for basic needs and two devices at one location. The key difference is that a switch is an active, intelligent device for expanding a network, while a splitter is a passive adapter for sharing one cable

You should replace the splitter with a unmanged tp-link switch so your not killing your speed. I don't think it will fix the IP conflict issue. 

  @HelpFixDecoApp My splitter is USB powered first i have to give power supply then my splitter start working and my splitter is providing internet to 4 devices at a time with 1000 Mbps speed. There is no problem on other devices.