help request: Failed to parse domain

Description

Context: I'm trying to build an application with an Auth Service which should only validate the tokens, and admin service which sould be protected.

I am running APIsix from docker container, but I keep getting errors about failing to parse the domain. When runing echo $variable_name inside the container, it echoes perfectly. But I still get these errors inside the log file.

The calls to the Auth service to check for the API are actually working, and the call to Admin service as well. But I still get these errors in the logs

On another hand, when effectuating these API calls from a front-end application, I get a CORS error, and I noted that the authorization header is not present inside the request sent with forward-auth plugin (even though I've added it inside the request_headers)

Here are the logs

2023/11/16 11:08:54 [error] 55#55: *160063 [lua] resolver.lua:80: parse_domain(): failed to parse domain: ${{AUTH_SERVICE_IP:=}}:${{AUTH_SERVICE_PORT:=3000}}, error: failed to query the DNSserver: dns server error: 3 name error, client: 172.21.0.1, server: _, request: "OPTIONS /auth/greet HTTP/1.1", host: "localhost:8080", referrer: "http://localhost:4200/"
2023/11/16 11:08:54 [error] 55#55: *160063 [lua] upstream.lua:79: parse_domain_for_nodes(): dns resolver domain: ${{AUTH_SERVICE_IP:=}}:${{AUTH_SERVICE_PORT:=3000}} error: failed to query the DNS server: dns server error: 3 name error, client: 172.21.0.1, server: _, request: "OPTIONS /auth/greet HTTP/1.1", host: "localhost:8080", referrer: "http://localhost:4200/"
2023/11/16 11:08:54 [error] 55#55: *160063 [lua] resolver.lua:80: parse_domain(): failed to parse domain: ${{AUTH_SERVICE_IP:=}}:${{AUTH_SERVICE_PORT:=3000}}, error: failed to query the DNSserver: dns server error: 3 name error, client: 172.21.0.1, server: _, request: "GET /auth/greet HTTP/1.1", host: "localhost:8080", referrer: "http://localhost:4200/"
2023/11/16 11:08:54 [error] 55#55: *160063 [lua] upstream.lua:79: parse_domain_for_nodes(): dns resolver domain: ${{AUTH_SERVICE_IP:=}}:${{AUTH_SERVICE_PORT:=3000}} error: failed to query the DNS server: dns server error: 3 name error, client: 172.21.0.1, server: _, request: "GET /auth/greet HTTP/1.1", host: "localhost:8080", referrer: "http://localhost:4200/"
2023/11/16 11:08:55 [warn] 55#55: *160063 [lua] plugin.lua:1107: run_plugin(): forward-auth exits with http status code 401, client: 172.21.0.1, server: _, request: "OPTIONS /admin/users HTTP/1.1", host: "localhost:8080", referrer: "http://localhost:4200/"

apisix.yaml

routes:
  - uri: /auth/*
    plugins:
      proxy-rewrite:
        regex_uri: ["^/auth/(.*)","/$1"]

    upstream:
      nodes:
        "${{AUTH_SERVICE_IP:=}}:${{AUTH_SERVICE_PORT:=3000}}": 1
      type: roundrobin
    
  - uri: /admin/*
    plugins:  
      proxy-rewrite:
        regex_uri: ["^/admin/(.*)","/$1"]
      forward-auth:
        uri: http://${{AUTH_SERVICE_IP:=}}:${{AUTH_SERVICE_PORT:=3000}}/validate
        ssl_verify: false
        request_headers: ["Authorization",authorization]
    upstream:
      nodes:
        "${{ADMIN_SERVICE_IP:=192.168.1.76}}:${{ADMIN_SERVICE_PORT:=3001}}": 1
    
#END

Environment

APISIX: 3.6 dockerized etcd:3.4.15 dockerized