当我的Nginx配置如下，并且后端tomcat运行在8080上时，Nginx无法与上游通信，并将浏览器重定向到https://backend：

upstream backend {
    ip_hash;
       server localhost:8080;
       server 10.10.1.240:80 down;
}
server {
    listen 80;
    listen 443 ssl;
    server_name ...;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
    ssl_certificate ...;
    ssl_certificate_key ...;
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 10m;
    add_header Strict-Transport-Security "max-age=31536000";

       location / {
        proxy_pass http://backend;

    }
}

但是当我的Nginx配置如下并且后端tomcat在8443上运行时，一切都运行正常，但是SSL终止目标没有实现：

upstream backend {
    ip_hash;
       server localhost:8443;
       server 10.10.1.240:80 down;
}
server {
    listen 80;
    listen 443 ssl;
    server_name ...;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
    ssl_certificate ...;
    ssl_certificate_key ...;
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 10m;
    add_header Strict-Transport-Security "max-age=31536000";

       location / {
        proxy_pass https://backend;

    }
}