502 Error Nginx in docker proxy to backend server - docker

Question

Help me please. I am trying to setup configuration with backend server in docker container and nginx container which is proxying requests to backend server.
Here is my configuration:
docker network inspect
[
{
"Name": "note",
"Id": "b58827aea0e606437a6be690f68c2f28226775da1cf060e5f3d66e8a7a5ecd2b",
"Created": "2023-01-14T21:09:25.741085061+05:00",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": {},
"Config": [
{
"Subnet": "172.19.0.0/16",
"Gateway": "172.19.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"4afa74e27d45b9a8aba8f2f9135ee60ea1dc8900cf8eaacd7b23edb9524fbc47": {
"Name": "backend",
"EndpointID": "5d3f7920df2db22bbd4d62f1a362642660931626524d097b5c3c9f0fbcecd464",
"MacAddress": "02:42:ac:13:00:02",
"IPv4Address": "172.19.0.2/16",
"IPv6Address": ""
},
"cc60ab137301a32c6b5daee5e185eb732460616e35a85b140900d388b305366b": {
"Name": "mongo",
"EndpointID": "6e2ba2aeed86c09e10ee60c32fbc9977fce3d50ee927ecaa081be8a906be6709",
"MacAddress": "02:42:ac:13:00:03",
"IPv4Address": "172.19.0.3/16",
"IPv6Address": ""
},
"fddcabdf6d5a676d381e08edf45315697940e05a38b9ebc36728820fa778a6eb": {
"Name": "nginx",
"EndpointID": "a25f40ad8967844d26ab247e81c17e5316d1774441d544157e7742bc3dd115a9",
"MacAddress": "02:42:ac:13:00:04",
"IPv4Address": "172.19.0.4/16",
"IPv6Address": ""
}
},
"Options": {},
"Labels": {}
}
]
docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
fddcabdf6d5a nginx "/docker-entrypoint.…" 11 minutes ago Up 11 minutes 0.0.0.0:8080->80/tcp, :::8080->80/tcp nginx
cc60ab137301 mongo:latest "docker-entrypoint.s…" 55 minutes ago Up 55 minutes 0.0.0.0:27017->27017/tcp, :::27017->27017/tcp mongo
4afa74e27d45 registry.gitlab.com/noteit/backend:master "/bin/sh -c 'npm run…" 55 minutes ago Up 55 minutes 0.0.0.0:3002->3001/tcp, :::3002->3001/tcp backend
nginx.conf
events {
worker_connections 1024;
}
http {
include mime.types;
upstream backend {
server backend:3002;
}
server {
listen 80;
location /api {
proxy_pass http://backend;
}
location /auth {
proxy_pass http://backend;
}
location / {
return 500;
}
}
}
So, request to http://localhost:8080/auth/login recives 502 response from nginx.
In nginx logs I see:
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2023/01/15 15:20:37 [error] 31#31: *2 connect() failed (111: Connection refused) while connecting to upstream, client: 172.19.0.1, server: , request: "POST /auth/login/ HTTP/1.1", upstream: "http://172.19.0.2:3002/auth/login/", host: "localhost:8080"
172.19.0.1 - - [15/Jan/2023:15:20:37 +0000] "POST /auth/login/ HTTP/1.1" 502 157 "-" "PostmanRuntime/7.29.2"
Explain me please, how can I solve it?
I tried to search the solution, but all my tries were unsucsessful.