Multiple tunnels with api requests - ngrok

I have 3 PORTS. One for my API, one for a back-office and one for my front-end.

I made this configuration file :

tunnels:
  front:
    addr: 4000
    proto: http    
  api:
    addr: 3000
    proto: http
  admin:
    addr: 3001
    proto: http

The problem is, I can't log in because the api request URL is wrong.

I saw on ngrok that we can rewrite headers. Is it possible to do it with multiple ports ?

Here is my network when I try to log in :