解决办法

打开 /www/server/panel/vhost/nginx 下的 你后台免端口访问的域名.conf

打开后类似于这样：

server
{
    listen 443;
    server_name control.xxcc.link;
    root /www/wwwroot/panel_ssl;

#PROXY-START/

ssl_certificate    /www/server/panel/ssl/certificate.pem;
ssl_certificate_key    /www/server/panel/ssl/privateKey.pem;
ssl_ciphers EECDH+CHACHA20:EECDH+CHACHA20-draft:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;
ssl_prefer_server_ciphers on;
ssl_session_cache shared:SSL:10m;
ssl_session_timeout 10m;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; #表示使用的TLS协议的类型。
location ^~ /
{
    proxy_pass https://127.0.0.1:XXXXX/;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header REMOTE-HOST $remote_addr;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $upgrade;
    
    proxy_http_version 1.1;
    # proxy_hide_header Upgrade;
    add_header X-Cache $upstream_cache_status;
    #Set Nginx Cache
}
#PROXY-END/
}

然后将location块下面的upgrade进行修改。因日志提示：

nginx: [emerg] unknown “upgrade” variable

所以应该就是upgrade这个变量无法识别，也有可能因为我的环境是nginx1.27.1。比较新，去掉了upgrade变量

改成如下：

    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $http_upgrade;

保存后，重启nginx即可。