@deepthinker To be honest sounds like a bad cable(s) i have listed some common trouble shooting problems below. Please see the section in bold. i would make sure your network is set up using one of...

@David-TP

@Gabor_Somogyi I see there might be a new firmware update for your deco I would go into your deco app and see if you can download and install that version 1st. If the new version isn't there or...

@Pessimism4567 I know the Deco X55/X50 with hardware version V1 support it not sure of any other models. The compare tool might have this info https://www.tp-link.com/us/deco-mesh-wifi/product-family/

@David-TP

@Lancslad1 i would make sure your network is set up using one of the examples in the post below https://community.tp-link.com/en/home/forum/topic/98898 and that your network switch is compatible with...