u.default_port = 80; in ngx_http_upstream_server

add a new upstream

upstream ssl_myappliationsite.net {
ip_hash;
server backendappsite1.net:443;
server backendappsite2.net:443;
server backendappsite3.net:443;
}

server {

listen 443 ssl;
server_name myapplicationsite.net;
keepalive_timeout 70;

ssl_certificate /appssl/fd.crt;
ssl_certificate_key /appssl/lb.key;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers HIGH:!aNULL:!MD5;

location / {
proxy_pass http://ssl_myappliationsite.net;
proxy_set_header HOST myapplicationsite.net;

}
}