Authentication Configuration Issue with NGINX Ingress, OAuth2 Proxy, and Azure Active Directory in Kubernetes

Question

I am facing authentication issues while configuring NGINX Ingress with OAuth2 Proxy and Azure Active Directory in my Kubernetes environment. Adding specific annotations to my Ingress resource results in a 401 Unauthorized error during the OAuth2 authentication flow. Seeking assistance to identify and resolve the root cause. Detailed error logs and configuration snippets are provided

apiVersion: networking.k8s.io/v1
kind: Ingress

metadata:
  annotations:
    nginx.ingress.kubernetes.io/auth-signin: https://$host/oauth2/start?rd=https://$host$request_uri
    nginx.ingress.kubernetes.io/auth-url: https://$host/oauth2/auth
  name: ingress
  namespace: xxx
spec:
  ingressClassName: nginx
  rules:
  - host: xxxx
    http:
      paths:
      - backend:
          service:
            name: xxxx
            port:
              number: 80
        path: /
        pathType: Prefix
  tls:
  - hosts:
    - xxxx
    secretName: xxxx

Logs below:

10.244.0.1 - - [11/Jan/2024:14:38:45 +0000] "GET /oauth2/auth HTTP/1.1" 401 13 "-" "python-httpx/0.24.1" 494 0.010  [] 10.244.1.23:4180 13 0.009 401 252a066e4116ec3c3f21e42cd6b52cdf
10.244.3.6 - - [11/Jan/2024:14:38:45 +0000] "GET /api/work_queues/name/default HTTP/2.0" 302 138 "-" "python-httpx/0.24.1" 91 0.019  [] - - - - 252a066e4116ec3c3f21e42cd6b52cdf
10.244.3.6 - - [11/Jan/2024:14:38:45 +0000] "GET /oauth2/start?rd=https://xxx/api/work_queues/name/default HTTP/2.0" 302 458 "-" "python-httpx/0.24.1" 67 0.008 [] 10.244.1.23:4180 458 0.007 302 88ae0533fd5c0b3588d577fca7ed2e1c

"I attempted to change the path from '/' to '/xxx', and interestingly, the authentication process works successfully when the path is set to '/xxx'. However, authentication fails when the path is configured as '/'. I expected the authentication to work seamlessly with the path set to '/'. Seeking guidance to resolve this issue.

  - backend:
      service:
        name: xxxx
        port:
          number: 80
    path: /
    pathType: Prefix