You will need to update your WordPress configuration file if your database has moved or changed in certain ways.
You will only need to modify the config file if:
your database has moved to another server and is not running on your localhost
you have renamed your database
you have changed the database user name
"'Make a backup copy of your wp-config.php file.'"
Open the >wp-config.php file in a text editor.
Review its contents. In particular, you are looking for the database host entry.
Save the file.
At this point, your WordPress blog should be working.
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