@kcdenton 

Thanks for reaching out. I understand that you are experiencing two main issues: your Deco Mesh LAN (Ethernet) connection is not working after previously functioning, and you are unable to connect or manage your Deco system using the Deco mobile app, as it only offers first-time setup instead of connecting to your existing network.

Here are some steps to help resolve both issues:

1. Deco App Connection Issue:
• If the Deco network was originally set up using the engineer's device and TP-Link account, your own app will not be able to manage the existing Deco network unless you are logged in with the same TP-Link account used during setup.
• To regain management access, you can:
    • Ask the engineer for the TP-Link account credentials (if possible), or
    • Perform a factory reset on all Deco units and set up the network again using your own TP-Link account via the Deco app. Please note this will erase all current settings, including Wi-Fi name and password.
• When setting up, ensure:
    • Only one Deco unit is powered on and flashing blue.
    • Your phone is connected to the Deco_XXXX Wi-Fi network during setup.
    • VPN is disabled on your phone/tablet.
    • The Deco is connected to your modem/router with a good Ethernet cable.
• If you see error messages such as "We couldn't find Deco" or "Ethernet Cable is Not Connected," try using a different Ethernet cable or port, and ensure you are close to the Deco unit.
• For more details, please refer to the FAQ: https://www.tp-link.com/support/faq/2239/

2. LAN (Ethernet) Connection Issue:
• If your PC previously obtained an IP address via DHCP but now cannot, try the following:
    • Ensure your PC's network adapter is set to obtain an IP address automatically (DHCP).
    • Try a different Ethernet cable and port on the Deco.
    • Reboot both your PC and the Deco unit.
    • If you manually set a static IP for a previous transfer, double-check that all settings have been reverted to automatic.
• If the Deco's LED is solid red, it indicates no Internet connection. In this case:
    • Connect a PC directly to your ISP modem/router to confirm the Internet is working.
    • Reboot the modem and Deco.
    • If your PC has Internet but Deco does not, you may need to use the Mac Clone feature. Instructions: https://www.tp-link.com/support/faq/2925/

Note: If these steps do not resolve your issues, you may need to contact TP-Link support for further assistance.

Let me know if you need more detailed instructions for any of the steps above.