Nginx redirects all websites to another website

I've been facing some weird issue. I have 2 WordPress websites installed on my server. I will call them,

example1.com, example2.com

All 2 websites run on Nginx, PHP-7.2, MariaDB and Ubuntu 18.04.

example1.com works fine. It was the very first website I installed. When I installed the 2nd website which is example2.com it worked fine until the installation was completed. However, after a few moments it started to show me a blank homepage. All headers were normal, it's just the blank website.

When I type example2.com/wp-admin is redirects me to example1.com/wp-admin. All websites work in https.

Here are my nginx.conf.

user tharindu;
worker_processes 2;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 2048;
    multi_accept on;
    use epoll;
}

http {

    ##
    # Basic Settings
    ##

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 10;
    types_hash_max_size 2048;
    server_tokens off;
    client_max_body_size 64m;

    # server_names_hash_bucket_size 64;
    # server_name_in_redirect off;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ##
    # SSL Settings
    ##

    ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
    ssl_prefer_server_ciphers on;
    ssl_ciphers "ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS";
    ssl_session_cache shared:SSL:20m;
    ssl_session_timeout 10m;
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

    ##
    # Logging Settings
    ##

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    ##
    # Gzip Settings
    ##

    gzip on;

    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 3;
    # gzip_buffers 16 8k;
    # gzip_http_version 1.1;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

    ##
    # Security
    ##

    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Xss-Protection "1; mode=block" always;
    add_header Content-Security-Policy "default-src 'self' https: data: 'unsafe-inline' 'unsafe-eval';" always;

    ##
    # Cache Settings
    ##

    fastcgi_cache_key "$scheme$request_method$host$request_uri";
    fastcgi_cache_use_stale error timeout invalid_header http_500;
    fastcgi_ignore_headers Cache-Control Expires Set-Cookie;
    add_header X-FastCGI-Cache $upstream_cache_status;

    ##
    # Virtual Host Configs
    ##

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;

    server {
        listen 80 default_server;
        listen [::]:80 default_server;
        server_name _;
        return 444;
    }
}

Here's my server block for example1.com

fastcgi_cache_path /var/run/nginx-cache levels=1:2 keys_zone=EXAMPLE1:100m inactive=60m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name www.example1.com;

    ssl_certificate /etc/letsencrypt/live/example1.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example1.com/privkey.pem;

    access_log /var/www/example1.com/logs/access.log;
    error_log /var/www/example1.com/logs/error.log;

    root /var/www/example1.com/public_html;

    index index.php;

    include global/cache-rules.conf;

    location / {
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

        fastcgi_cache_bypass $no_cache;
        fastcgi_no_cache $no_cache;
        fastcgi_cache EXAMPLE1;
        fastcgi_cache_valid 200 60m;
    }

    location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
        expires max;
        log_not_found off;
    }
}

server {
    listen 80;
    listen [::]:80;
    server_name example1.com www.example1.com;

    ssl_certificate /etc/letsencrypt/live/example1.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example1.com/privkey.pem;

    return 301 https://www.example1.com$request_uri;
}

Here's my server block for example2.com

fastcgi_cache_path /var/www/example2.com/cache levels=1:2 keys_zone=EXAMPLE2:100m inactive=60m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name www.example2.com;

    ssl_certificate /etc/letsencrypt/live/example2.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example2.com/privkey.pem;

    access_log /var/www/example2.com/logs/access.log;
    error_log /var/www/example2.com/logs/error.log;

    root /var/www/example2.com/public_html;

    index index.php;

    include global/cache-rules.conf;

    location / {
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

        fastcgi_cache_bypass $no_cache;
        fastcgi_no_cache $no_cache;
        fastcgi_cache EXAMPLE2;
        fastcgi_cache_valid 200 60m;
    }

    location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
        expires max;
        log_not_found off;
    }
}

server {
    listen 80;
    listen [::]:80;
    server_name example2.com www.example2.com;

    ssl_certificate /etc/letsencrypt/live/example2.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example2.com/privkey.pem;

    return 301 https://www.example2.com$request_uri;
}

I have used these configurations to redirect all versions of URLs to https://www.

How can I stop seeing this blank pages and at the same time stop redirecting?