@ronik 

Hi, Thank you very much for your feedback.

When main Deco went solid red, it means X20-DSL was disconnected from the internet service provider.

Then a few more steps to help us understand what happened:

1. Please go to Deco APP>More>Advanced>IPV4 and check whether you could still get a valid IPV4 address.

--If the IP is 0.0.0.0, it is very likely there is something wrong with the DSL service provider.

2. if the IP address did not change, please try to restart the main Deco X20-DSL once.

If restarting Deco helps get the connection back and the LED turns green this time, the disconnection is temporary and Deco is not bricked.

(as you asked in the other post, usually we will call Deco"brick" when it no longer responds to a hardware reset.)

Thank you again.

Wait for your reply.

best regards.

  @ronik 

Hi, Thanks for the update.

The attached pictures said the DSL line has been successfully synced from the provider but somehow you might put the incorrect internet credentials.

Have you ever checked with the provider what is your internet connection type and whether you have put the correct PPPoE username and password?

Best regards.

  @ronik 

Sorry for the delay.

When I checked via your TP-Link ID, I happen to see there is a TD-W9970.

So currently TD-W9970 is working well with your internet service provider with the same internet configuration as Deco X20-DSL, right?

If yes, you could have a check of the internet settings on the 9970, such as VID:

If it failed again, please feel free to send an email to support.forum@tp-link.com with a screenshot of the internet connections on your TD-W9970.

Thank you very much.

Best regards.