Hello  @Zorrro ,

Thanks for contacting our community.

It seems that you are experiencing an unstable internet connection on your TP-Link powerline devices. Here are some steps you can take to troubleshoot the issue:
    1. For wired powerline adapters, check if Power Saving Mode is enabled. You can disable it using the tpPLC utility. Refer to this FAQ for detailed instructions: How to enable/disable power saving mode on powerline adapters
    2. Move the powerline extender closer to the router and the powerline adapter. Placing them in the same room for testing.
    3. Test the internet connection by connecting your client devices directly to the main router. This will help determine if the issue is specific to the powerline connection or if it's a problem with the router itself.

Best Regards.

  @Zorrro powerline adapters are very sensitive to the electrical installation and if the Powerline LED goes off randomly it usually means the connection between the two units is interrupted
Heavy electrical devices like photovoltaic inverters can create interference and that’s likely why you see the dropouts at certain times of the day
Try to plug the adapters directly into wall sockets and not through power strips or the rack
If possible avoid sharing the same line with the PV inverter and also check if there is a newer firmware for your kit
If stability is critical the only real fix may be running a direct Ethernet cable or placing a Wi-Fi AP outside the enclosure since PLC is not always reliable in such environments