Nginx 400 bad request and nothing interesting in logs

I can't stop getting 400 bad request. After some research, I found out that this meant that the request had bad headers due to a bad configuration

Here is my nginx.conf file:

user  nginx;
worker_processes  auto;

events {
    worker_connections  1000;
}

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;

http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    server_tokens off;

    set_real_ip_from  192.168.0.0/16;
    set_real_ip_from  172.16.0.0/12;
    set_real_ip_from  10.0.0.0/8;
    real_ip_header    X-Forwarded-For;
    real_ip_recursive on;

    log_format  main  '$remote_addr - $remote_user "$request" '
                      '$status $body_bytes_sent $http_host "$http_referer" '
                      '"$http_user_agent"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    gzip on;
    gzip_disable "msie6";
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_http_version 1.1;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*.conf;
}

Here is the output to logs when I do a get request to the server:

" while reading PROXY protocol, client: 172.26.0.5, server: 0.0.0.0:80
2021/09/16 11:08:07 [error] 8#8: *8 broken header: "GET /favicon.ico HTTP/1.1
pragma: no-cache
cache-control: no-cache
sec-ch-ua: "Google Chrome";v="93", " Not;A Brand";v="99", "Chromium";v="93"
sec-ch-ua-mobile: ?0
user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.82 Safari/537.36
sec-ch-ua-platform: "Windows"
accept: image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8
sec-fetch-site: same-origin
sec-fetch-mode: no-cors
sec-fetch-dest: image
referer: https://localhost/
accept-encoding: gzip, deflate, br
accept-language: en-US,en;q=0.9
host: localhost
X-Forwarded-For: 172.26.0.1

This nginx reverse proxy is running on a docker container with the following dockerfile:

FROM nginx:1.16

ENV DOCKER_IMAGE nginx
ENV DOCKER_NAME nginx
ENV TZ Africa/Tunis

RUN set -x && \
    # tiny helper to reload nginx config
    printf '#!/bin/bash\n/usr/sbin/nginx -s reload\n' >> /usr/local/bin/nginx-reload && \
    chmod +x /usr/local/bin/nginx-reload && \
    # delete nginx default server config
    rm /etc/nginx/conf.d/default.conf

COPY ./conf/ /etc/

ENV WORKER_PROCESSES auto
ENV WORKER_CONNECTIONS 1024

ENV SERVER_NAME localhost

The nginx.conf has no configuration what to do with the requests, do you have any other configs e.g. in /etc/nginx/conf.d or in /etc/nginx/sites-enabled.

You can use the server block with the location block to configure a proxy or you can use the root directive to set it to an directory to send files out of it.

So to help you better do specify what do you want to make with nginx.