Nginx反向代理错误指向站点问题求助：新增子域名被异常重定向

大家好，我在Debian 12上用Nginx做带SSL终止的反向代理，托管了好几个站点，最近遇到了个奇怪的问题——没法新增更多主机了，具体情况如下：

• 我已经启用了默认站点，但只要浏览器访问sub-xx.domain.com这类新增的子域名，就会被系统重定向到a.domain.com；而从a.domain.com到w.domain.com这些已有的站点都能正常工作。
• 如果用HTTP访问，浏览器会提示站点不安全，然后被重定向到d.domain.com；如果明确用HTTPS访问，则会被重定向到a.domain.com。
• 查看xx.domain.com的日志，完全找不到请求记录；只有当用HTTPS访问时，a.domain.com的日志里会出现一条记录：

  192.168.9.1 - - [19/Jan/2024:16:55:04 -0300] "GET /img/logo.gif HTTP/2.0" 200 3418 "https://xx.domain.com/css/login>
  

下面是相关的配置文件，麻烦大家帮忙排查下问题：

新增站点xx.conf的配置 #

upstream xx {
    server 192.168.8.86;
    keepalive 32;
}

server {
    listen 80;
    server_name xx.domain.com;
    include /etc/nginx/snippets/location-letsencrypt.conf;
    #    return 301 https://$server_name$request_uri;
    #}

    #server {
    #    listen 443 ssl http2;
    #    server_name test.xx.domain.com;
    #    include /etc/nginx/snippets/location-letsencrypt.conf;
    #    include /etc/nginx/snippets/ssl-params.conf;
    #    ssl_certificate /etc/letsencrypt/live/xx.domain.com/fullchain.pem;
    #    ssl_certificate_key /etc/letsencrypt/live/xx.domain.com/privkey.pem;

    location / {
        include /etc/nginx/snippets/proxy.conf;
        proxy_pass http://test_xx/;
    }

    access_log /var/log/nginx/xx.domain.com/access.log;
    error_log /var/log/nginx/xx.domain.com/error.log;
}

另一个新增站点yy.conf的配置 #

upstream yy {
    server 192.168.8.81;
    keepalive 32;
}

server {
    listen 80;
    server_name yy.domain.com;
    include /etc/nginx/snippets/location-letsencrypt.conf;
    #    return 301 https://$server_name$request_uri;
    #}

    #server {
    #    listen 443 ssl http2;
    #    server_name yy.domain.com;
    #    include /etc/nginx/snippets/location-letsencrypt.conf;
    #    include /etc/nginx/snippets/ssl-params.conf;
    #    ssl_certificate /etc/letsencrypt/live/yy.domain.com/fullchain.pem;
    #    ssl_certificate_key /etc/letsencrypt/live/yy.domain.com/privkey.pem;

    location / {
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_cache_bypass $http_upgrade;
        proxy_pass_request_headers   on;
        proxy_pass http://yy/;
    }

    access_log /var/log/nginx/yy.domain.com/access.log;
    error_log /var/log/nginx/yy.domain.com/error.log;
}

主配置nginx.conf #

user www-data;
worker_processes auto;
worker_rlimit_nofile 100000;
pid /run/nginx.pid;

include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 10240;
    multi_accept on;
}

http {
    ##
    # Basic Settings
    ##

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    server_tokens off;
    server_names_hash_bucket_size 64;
    # server_name_in_redirect off;

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

    ##
    # To avoid error 413
    client_max_body_size 192M;

    ##
    # Logging Settings
    ##

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log debug;

    log_format  main  '$remote_addr - $remote_user [$time_local]
"$request" ' '$status $body_bytes_sent
"$http_referer" ' '"$http_user_agent"
"$http_x_forwarded_for"';

    #access_log /var/log/nginx/access-special.log combined;

    ##
    # Gzip Settings
    ##

    gzip on;

    ##
    # Virtual Host Configs
    ##

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

引用的snippet文件location-letsencrypt.conf #

location ^~ /.well-known/acme-challenge/ {
    allow all;
    default_type "text/plain";
    root /var/www/le_root;
}

location = /.well-known/acme-challenge/ {
    return 404;
}

折腾了好一阵没找到原因，有没有大佬能帮忙看看问题出在哪？

备注：内容来源于stack exchange，提问作者drodriguez