Transfer hosting

I just transfer my hosting provider. I export my mysql database to my PC and downloaded all my files to PC as well.

I then uploaded all the files back to the new hosting server, created the new database and imported back all the tables..

Then, i changed the database name, database user name and password in wp-config.php, have made sure that the database name, user name and user password is the same with the new database.

However, i am still getting “Error establishing a database connection”..

What have i done wrong??

Thanks