SQLSTATE[HY000] [1045] Access denied for user 'root'@'localhost' (using password: NO) . DB_HOST set to localhost

To be honest while working on laravel 6 i also faced this issue many times and probably was unable to figure out the solution i tried commands like php artisan config:cache and php artisan config:clear but these two commands didn't help.

To come over this issue you have to execute the all the below commands:

php artisan route:cache
php artisan route:clear
php artisan config:cache
php artisan config:clear
php artisan optimize

Note: Make sure in .env you have put db_password and it is not null and also check if your db_password uses any special character always enclose them in ""

Example:

DB_PASSWORD="%123456%"

To debug this issue you can also create a test route and then dump .env variable there to check if they have the correct values or not?

Route::get('/test/env', function () {
    dd(env('DB_DATABASE')); // dump db variable value one by one
});

Hope it helps.

Thanks

Note: Please Make sure to restart your server.

Make sure your DB credential and DB Host is set correctly :

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE="your_database_name"
DB_USERNAME="put_db_user_name _here"
DB_PASSWORD="put_db_password_here_if_have_set"

If you have not set any db password the put

DB_PASSWORD=""

The problem is that the project made a cache file 'config.php' must be deleted in order to allow the system to restart and you can do so by accessing this file and deleting it

bootstrap/cache/config.php