NPM proxy to nginx - error 502 #2897

Checklist

Have you pulled and found the error with jc21/nginx-proxy-manager:latest docker image?

Are you sure you're not using someone else's docker image?

Have you searched for similar issues (both open and closed)?

Describe the bug
Got 502 error when made proxy from NPM to nginx.

Nginx Proxy Manager Version
v2.10.2

To Reproduce
Steps to reproduce the behavior:

Use officially nginx image without any for application (app-front)

Run NPM

Make proxy to application via NPM for frontend

Make proxy to application via NPM for backend

Git error 502 when open frontend app. Backend works correctly.

Expected behavior

Make proxy for frontend app correctly.

Operating System
Docker - Debian

Additional context

Application is accessible via port 8080 so nginx from frontend part works correctly.

It looks like the problem is between NPM and nginx.

Error logs from NPM (IP 172.23.0.2 is frontend):
2023/05/07 08:45:59 [error] 9579#9579: *1174 connect() failed (111: Connection refused) while connecting to upstream, client: IP_CLIENT, server: krzysiek.dszymczuk.pl, request: "GET / HTTP/2.0", upstream: "http://172.23.0.2:8080/", host: "MYDOMAIN.COM", referrer: "http://MYDOMAIN.COM:8081/"

2023/05/07 08:46:00 [error] 9579#9579: *1174 connect() failed (111: Connection refused) while connecting to upstream, client: IP_CLIENT, server: MYDOMAIN.COM, request: "GET /favicon.ico HTTP/2.0", upstream: "http://172.23.0.2:8080/favicon.ico", host: "MYDOMAIN.COM", referrer: "https://MYDOMAIN.COM/"