I want to use my own AWS account (1XXXXXXXXXXX) with my Alexa skill instead of the default account (7XXXXXXXXXXX):

I created a skill in Alexa and I developed a Lambda function to host it in my AWS account 1XXXXXXXXXXX. In order to connect both of them, I changed Alexa's Endpoint to the arn link of my Lambda function. But when I try to test my Alexa skill, it redirects me to the federated default account with ID client 7XXXXXXXXXXX instead of mine, so it doesn't execute my lambda function.

I tried to change the execution roles for the default account 7XXXXXXXXXXX but this account has no permission to do anything, not even creating new permissions or roles.

What else can I try?