How to allow default Heroku domain for OAuth1?

Hello, I am trying to fetch data from the api.
I made a small app that I deployed to heroku.

Unfortunately, the CH API is returning me 403 status code (forbidden response).
I have tried to set the domain in the javascript domain: https://{myappname}

And it seems the API is not mapping it to my server.

Is there a specific default domain for Heroku I should set, for the API to work?
I am using the default domain name from heroku: https://{myappname}

Thank you