can't change user linked to the product

This is the user (the one with which I’m posting) that I want to have linked to my Avast installation.
Instead another account is currently linked, without point on trying to use either the “add account” or “remove account” options.
The “add account” says “sorry but couldn’t connect the account”.
The “remove account” does nothing.

Avast version: 12.3.2280 (build 12.3.3154.22)
Windows 8

any help is appreciated

https://forum.avast.com/index.php?board=62.0