Microk8s reaches internet but not internal network - kubernetes

Question

I've just installed Ubuntu 22.04 on a vmware virtual server and started using microk8s. The server is part of a local network in which there are some servers, including microsoft AD and IIS servers that handle the network.
I've docker installed on the ubuntu system and can run all the containers of the web app with no problem via docker. In particular, I have a service (a container) that connects to the windows AD server of the local network to authenticate users of the web app. On the host, it works with no problem, can reach the AD server and also other servers in the network and do all the necessary operations.
On the other hand, when run on kubernetes via microk8s, all the services work, they are all reachable from the local network, while at the same time the containers can reach the external network (outside our local network, e.g. www.google.com). Only the internal network seems to be unreachable, for which I always get a timeout error.
What I tried (but did not work)
External service
[https://kubernetes.io/docs/concepts/services-networking/service/#services-without-selectors][1]
Check the dns resolution on the host that gets copied into the container
Note
I'm not sure what kind of commands shall be run in order to provide the most useful information about the configuration, so I'll be iterating over this question, extending it with logs and other meaningful information.
Thanks
Edit 11/10/2022
I've enable the following addons
microk8s is running
high-availability: no
datastore master nodes: 127.0.0.1:19001
datastore standby nodes: none
addons:
enabled:
dns # (core) CoreDNS
ha-cluster # (core) Configure high availability on the current node
helm # (core) Helm - the package manager for Kubernetes
helm3 # (core) Helm 3 - the package manager for Kubernetes
ingress # (core) Ingress controller for external access
metallb # (core) Loadbalancer for your Kubernetes cluster
Another strange thing, is that the containers can access the postgres database on the host via the host's ip address (10.1.1.xxx)
Edit 2 12/10/2022
Here's the ingress yaml file
apiVersion: v1
kind: Service
metadata:
name: ingress
namespace: ingress
spec:
selector:
name: nginx-ingress-microk8s
type: LoadBalancer
ports:
- name: http
protocol: TCP
port: 80
targetPort: 80
- name: https
protocol: TCP
port: 443
targetPort: 443
---
#
# Ingress
#
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: main-ingress
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
rules:
- http:
paths:
- path: /api/erp(/|$)(.*)
pathType: Prefix
backend:
service:
name: erp-service
port:
number: 8000
- path: /api/auth(/|$)(.*)
pathType: Prefix
backend:
service:
name: auth-service
port:
number: 8000
- path: /()(.*)
pathType: Prefix
backend:
service:
name: ui-service
port:
number: 3000
I can access the UI and by using the host's ip and /api/auth, I can access the online documentation of swagger/openapi.
[1]: https://kubernetes.io/docs/concepts/services-networking/service/#services-without-selectors

Answer 1

To this day I haven't managed to find any solution but to circumvent the request and use a "proxy" endpoint as suggested in
Accessing an external InfluxDb Database from a microk8s pod using selectorless service and manual endpoint?
Basically, it creates a service with that can be accessed by the cluster and an endpoint that points to the external resource.
Actual source config taken from the answer
kind: Service
apiVersion: v1
metadata:
name: influxdb-service-lb
#namespace: ingress
spec:
type: LoadBalancer
loadBalancerIP: 10.1.2.61
# selector:
# app: grafana
ports:
- name: http
protocol: TCP
port: 8086
targetPort: 8086
---
apiVersion: v1
kind: Endpoints
metadata:
name: influxdb-service-lb
subsets:
- addresses:
- ip: 10.1.2.220
ports:
- name: influx
protocol: TCP
port: 8086
If I'll manage to find a solution, I'll update this answer