Nginx Directory Index is Forbidden

I Have Laravel Rest Api for mobile app running under ubuntu - nginx and every thing is working just fine till today, woke up and users can’t access the api and I check nginx error log and found below

2021/04/18 01:21:52 [error] 2772#2772: *138808 directory index of "/var/www/html/mydomain/public/" is forbidden, client: 9x.1x.1x.5x, server: mydomain.com, request: "GET / HTTP/1.>
2021/04/17 23:16:01 [error] 2772#2772: *138792 directory index of "/var/www/html/mydomain/public/" is forbidden, client: 4x.15x.20x.2x1, server: mydomain.com, request: "GET /?XDEBUG>

this is my Nginx config :

server {

    
    root /var/www/html/mydomain/public;

    # Add index.php to the list if you are using PHP
    index index.php;

    server_name mydomain.com www.mydomain.com;

    location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to displaying a 404.
        try_files $uri $uri/ /index.php?$query_string;
    }

    # pass PHP scripts to FastCGI server
    #
    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
    #
    #   # With php-fpm (or other unix sockets):
        fastcgi_pass unix:/var/run/php/php7.3-fpm.sock;
    #   # With php-cgi (or other tcp sockets):
    #   fastcgi_pass 127.0.0.1:9000;
    }

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    location ~ /\.ht {
        deny all;
    }

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot


}

server {
    if ($host = www.mydomain.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = mydomain.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    listen 80;
    listen [::]:80;

    server_name mydomain.com www.mydomain.com;
    return 404; # managed by Certbot

No one changed any thing on the server side and it was working, what is the issue here

Appreciate any help and ideas this is a live project