How to set correct host for action-text-attachment figure img src?

My rails 6 app is set up with amazon s3 with a react front-end.
I serve the react front-end with json and in my json I have Post model with a rich content body.
In the body I have added an image. When I serve the body in the json (body.body.to_s), the figure img src inside the action-text-attachment for my image uses http://example.org instead of my rails app hostname.
I tried setting default url options host to no avail. Please, I've looked through the internet for anything that could help and come up with nothing.