Error establishing a database connection after changing wp-config.php values back

Earlier today my website worked fine. Then I changed the DB_Name, DB_User and DB_Password in my wp-config.php file to the production website’s values. Afterward, I got “Error establishing a database connection”. I immediately changed them back to their previous values, but I still keep getting this error message. I created the website by doing a ‘git clone’, and I’ve even copied the wp-config.php by doing a Ctrl-A from the GitHub repository to my laptop. I still keep getting this error message. Any idea why?