nginx代理tomcat服务器，代理用http，tomcat重定向的页面无法访问，什么原因？

整体结构
用户--https-->Nginx--http-->Tomcat
页面中包含了iframe,iframe的src也是Https的,但是当frame里面的内容表单提交后tomcat服务器处理成功想要重定向却无法正常重定向,Chrome报错如下
Mixed Content: The page at 'https://...../#' was loaded over HTTPS, but requested an insecure form action 'http://...//'. This request has been blocked; the content must be served over HTTPS.
我实在不知道怎么正确组织语言描述这个问题,不知道描述的大家能否理解,下面贴上Nginx的配置信息,希望大家抽时间帮忙看看,先谢过了

proxy.conf
proxy_redirect          off;
proxy_set_header        Host $host;
proxy_set_header        X-Real-IP $remote_addr;  #获取真实ip
client_max_body_size    10m;
client_body_buffer_size 128k;
proxy_connect_timeout   90;
proxy_send_timeout      90;
proxy_read_timeout      90;
proxy_buffer_size       4k;
proxy_buffers           4 32k;
proxy_busy_buffers_size 64k;

proxy_temp_file_write_size 64k;

defalut

server {
listen 80 default_server;

server_name localhost;

return 301 https://$server_name:6663$request_uri;
}

server {
listen 6663;

server_name localhost;

ssl     on;
ssl_certificate      /home/dream/Https/ssl/server/server.crt;
ssl_certificate_key  /home/dream/Https/ssl/server/server.pem;
ssl_client_certificate /home/dream/Https/ssl/server/root.crt;
 
ssl_session_timeout  5m;
ssl_verify_client on;  #开户客户端证书验证

ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;
ssl_prefer_server_ciphers on;

location / {
proxy_pass http://127.0.0.1:8080/;
}
}

系统环境:
nginx version: nginx/1.4.6 (Ubuntu) built by gcc 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
Ubuntu 14.04
Chrome版本 42.0.2311.135 (64-bit)