Mysql Database connection denied - php

Question

I am trying to get my Symfony 3 app running in production mode on an Amazon EC2 instance.
I am have the code in the correct place, and then I try to setup any dependencies with composer by running
export SYMFONY_ENV=prod
composer install --no-dev --optimize-autoloader
but get the error
> Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::installAssets
[Doctrine\DBAL\Exception\ConnectionException]
An exception occured in driverL SQLSTATE[HY000] [1044] Access denied for user 'my-user'#'127.0.0.1' to database 'my_database'
This error is then passed down to [Doctrine\DBAL\Driver\PDOException] and [PDOException] before the script terminates.
This is then followed by the message
[RuntimeException]
An error occured when executing the "'assets:install --symlink --rela'\''web'\'''" command:
which is then followed by the same errors as at the beginning.
My parameters.yml file is
parameters:
database_host: 127.0.0.1
database_port: 3306
database_name: my_database
database_user: my-user
database_password: mypassword
server_version: 5.6
mailer_transport: smtp
mailer_host: 127.0.0.1
mailer_user: null
mailer_password: null
secret: Mysecret
registration_permitted: true
registration_limit: 3
and the user my-user has all permissions on the database my_database except GRANT.
I have been trying to solve this for a few hours to no avail, other solutions I came across involved misspelt usernames/passwords/databases (triple-checked) or needed the server version adding (which hasn't made a difference).
Additional Info
Running mysql -u my-user -p prompts for the password and then allows me to log in.
Running mysql -u my-user -p -D my_database prompts for the password and then returns ERROR 1044 (42000): Access denied for user 'my-user'#'localhost' to database 'my_database'.
Logging into mysql as root and running SHOW GRANTS FOR 'my-user'; returns ERROR 1141 (42000): There is no such grant defined for user 'my-user' on host '%'.
Logging into mysql as root and running SHOW GRANTS FOR 'my-user'#'localhost'; returns GRANT USAGE ON *.* TO 'my-user'#'localhost' IDENTIFIED BY PASSWORD hashedPassword.
Additional Info 2
After deleting my-user ('my-user'#'localhost' and 'my-user'#'127.0.0.1') and then recreating them using GRANT ALL PRIVILEGES ON my_database.* TO 'my-user'#'localhost' IDENTIFIED BY 'password'; and also GRANT ALL PRIVILEGES ON my_database.* TO 'my-user'#'127.0.0.1' IDENTIFIED BY 'password'; and then FLUSH PRIVILEGES; The output of SHOW GRANTS FOR 'my-user'#'localhost' is then
GRANT USAGE ON *.* TO 'my-user'#'localhost' IDENTIFIED BY PASSWORD 'passwordHash'
GRANT ALL PRIVILEGES ON 'my_database' TO 'my-user'#'localhost'
and similar output for 'my-user'#'127.0.0.1'.
But this is still giving me the same errors as before, any more ideas?

Answer 1

As discussed in comments you did not have any privilege on the database.
So running this fixes your problem:
GRANT ALL PRIVILEGES ON my_database.* TO 'my-user'#'localhost'
About your doubt why you had to change it to localhost in your params because that's what you're telling mysql
Imagine you want to restrict database access to only a specific ip in your network you could run
GRANT ALL PRIVILEGES ON my_database.* TO 'my-user'#'192.168.1.10'
So replace 192.168.1.10 with 127.0.0.1 and you can use 127.0.0.1 in your parameters