NodeJS demo failing with test credentials

[hernan-fernandez]

a payment with test credentials is failing, with production credentials works ok

I'm adding the PUBLIC KEY to /client/html-js/js/index.js
and the ACCESS TOKEN to /server/node/server.js

The link is generated, I try to pay with the test cards [1]

However In last step I receive this error.
This demo was working for me last week. Now not sure if this is an issue with my account. I tested from different computers, IP, browsers and even created new applications with no luck.

[1] https://www.mercadopago.cl/developers/en/docs/your-integrations/test/cards