We actually need to add Portuguese translation to support that language. Until it is added to the skill, you will not be able to use the official skill unfortunately.
Have you tried to deploy your private skill? The localization in that setup may not be a factor. Also, I am curious to see which region the Lambda function should be deployed since Amazon hasn’t updated their documentation for your skill language as of yet. My guess would be with the North America endpoint (us-east-1). It would be great if you could confirm? 