Since yesterday, when I tried to buy some games, when I go to the checkout I can see this message referred to PayPal:
"Selected payment method is currently unavailable, please choose a different one."

Anywhere else, as far as I know, PayPal is working well for me, I -apparently- only have this problem in GOG. Never had this issue in Gog previously. My question is, is the problem on my side, or a region problem? (I'm in Spain )
Is there anybody else having this issue as well?

thanks

PayPal worked fine for me two days ago, might want to contact support. You could try to add money to the GOG Wallet that way you can at least buy the games until this PayPal thing get sorted out.

Do you use any plugins like noscript? If yes, maybe you're blocking something critical for Paypal. It works on my end, but i do get the same error as you if i block the Braintree service as well a couple of others.

I had already thought of it, and checked for any unwanted blocking (I use Domain Blocker), but it was blocking nothing.
But you made me think twice about it, and check for Duck Duck Go Privacy Essentials... and that was it. If I disable it, PayPal is available (it's curious that it was the only payment option blocked).

Hope this thread will be helpful if somebody else has the same problem.