Failed to connect to mysql at 127.0.0.1:3306 with user root access denied for user 'root'@'localhost'(using password:YES)

Access the database as a user administrator (root user maybe). Check the right one user privileges to the database.

mysql >SHOW GRANTS FOR <username>;

Assign full user privileges to the database from localhost

mysql> GRANT ALL PRIVILEGES ON <databasename>.* TO '<username>'@'localhost' IDENTIFIED BY '<password>';
mysql> FLUSH PRIVILEGES;

in case of error in connecting to the database from third-party programs, for example MySQL WORKBENCH, assign privileges to the user to the database from any host
MYSQL Grant all privileges to database from any host

mysql> GRANT ALL PRIVILEGES ON <databasename>.* TO '<username>'@'%' IDENTIFIED BY '<password>';
mysql> FLUSH PRIVILEGES;