the error is telling you that the connection information that was entered is not correct. The MySQL server Is not allowing access because either the Server Name, Username or password used in the connection are incorrect.
If you are 100% Sure the information is correct, it may be that the MySQL Server does not allow connections from an outside source like your client computer.
Contact your host to find out if the MySQL has any connection limitations, or for help determining the correct Server Address, username and password to use for createing the database connection.