Problem with CORS policy when VueJs App with revers Proxy

[renanbronchart]

Hello,
I have a problem with cors policy when Vue Js app is in served by a reverse proxy (rack-reverse-proxy).

I can't access to my main.js because a content security policy.
The problem appear just in server side, not in client side.

My Vue.js App is served by proxy with port localhost:3000.

Do you know how to fix it?

Thanks a lot :)