Error establishing a database connection

Could mean a number of things, did you get the error after a new install or was your site up and running? Could be the database crashed or could be a mistake in the wp-config.php.

Thanks for replying!
Its brand new- I think its the wp-config.php but I have no idea how to go in and change it?!

Ok brand new, so the site hasn’t worked once since you installed it? That prob means a error in the config.php. You need to check the file and see what it says. Open up ftp and navigate to your wp-directory. There you will find a file called wp-config.php. Open it and check your username, datbase etc.