Route 53 isn't letting me access to the ec2 instance through the application load balancer - amazon-web-services

Question

I built a rails app in ec2 instance and deployed using route 53.
Currently I succeeded in associating the instance with the domain provided by amazon.
I can access to the page with the domain name.
However, once I create a record and associate the domain to the alb, I'm no longer able to access to the page.
I'm doing it to make the https access available.
I checked the things below.
Target group succeeds health check
Typing the DNS name of ALB works with both http and https
The record on route53 shows the DNS name above
The security group used for the ALB allows all the access
regardless of either http or https
listener is configured for both http and https
I also checked the article below
Unable to Access HTTPs in AWS Application Load Balancer EC2 Instance
I have no idea of what else to check after all.
Please help me.
I've been working on this the whole day...
Here's my config files
ruby_gems_bootcamp.conf(for nginx)
;; Query time: 6 msec
# log directory
error_log /var/www/rails/ruby-gems-bootcamp/log/nginx.error.log;
access_log /var/www/rails/ruby-gems-bootcamp/log/nginx.access.log;
# max body size
client_max_body_size 2G;
upstream app_server {
# for unix domain socket setups
server unix:/var/www/rails/ruby-gems-bootcamp/tmp/sockets/.unicorn.sock fail_timeout=0;
}
server {
listen 80;
server_name 54.248.194.243
# nginx so increasing this is generally safe ...
keepalive_timeout 5;
# path for static files
root /var/www/rails/ruby-gems-bootcamp/public;
# page cache loading
try_files $uri/index.html $uri.html $uri #app;
location #app {
# http headers
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
# referring upstream app_server
proxy_pass http://app_server;
}
# Rails error pages
error_page 500 502 503 504 /500.html;
location = /500.html {
root /var/www/rails/ruby-gems-bootcamp/public;
}
}
nginx.conf
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
# Load dynamic modules. See /usr/share/doc/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;
events {
worker_connections 1024;
}
http {
log_format main '$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.log main;
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 4096;
include /etc/nginx/mime.types;
default_type application/octet-stream;
# Load modular configuration files from the /etc/nginx/conf.d directory.
# See http://nginx.org/en/docs/ngx_core_module.html#include
# for more information.
include /etc/nginx/conf.d/*.conf;
server {
listen 80;
listen [::]:80;
server_name _;
root /usr/share/nginx/html;
# Load configuration files for the default server block.
include /etc/nginx/default.d/*.conf;
error_page 404 /404.html;
location = /404.html {
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
}
}
}
route53 configuration