Hello folks
I bought a 30€ version of Blood and Wine and I wanted to change the code into a steam one,
as it is possible to do with thewitcher.com/exchange.
But the code I put in is labelled as "This GOG code cannot be found".
I did the same thing with the previous "heart of stone" and it worked.
Is there a possible solution to this?

There are a lot of key resellers that do shady things. Where did you buy the key from? Some place like GreenManGaming or some such? If you used a reseller, you maybe need to start communication with them, since there aren't very many places that sell officially supported keys for Witcher 3.

You need to contact support. No one in this forum can help with verifying keys.

nevermind

Ok, it settled by itself.

Thanks to the gog.com support!

Lock the topic if needed.