Nginx can't resolve server names when loading them from a file - dictionary

Question

I'm new to nginx and trying to achieve the following behaviour: I want to pass an header to nginx and pass the request to another server based on the given header. I want to load my map from a file so i'm using the following code
worker_processes 1;
error_log logs/error.log;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
sendfile on;
tcp_nopush on;
keepalive_timeout 65;
map $http_dest $new_server{
include port_to_address.map;
default google.com;
}
server {
listen 200;
server_name localhost;
access_log logs/host.access.log main;
location / {
proxy_pass http://$new_server;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}
with the port_to_address.map in the following format
value_1 yahoo.com;
value_2 neflix.com;
With This configuration nginx starts normally but when i pass him an header that exists in the file he returns the following error
2021/04/18 21:52:49 [error] 17352#20504: *3 no resolver defined to resolve yahoo.com, client: 127.0.0.1, server: localhost, request: "GET / HTTP/1.1", host: "localhost:200"
When i'm using the ip address and not the server's name it works perfectly. I also got another nginx thats round-robin requests between nodes it reads from a file (with upstream) and there i doesn't get any exception although im using the server's name and not their ip.
I read about using resolver but it doesn't work and i prefer to avoid it. Is there any other way to make it work without using the resolver or the servers ip? (I dont mind changing the map file structure if needed)