Playsterr on "Receiving Error establishing a database connection"

Hello dear community.
I have migrated my WP site to another hosting today.
Unfortunately now I am receiving "Error establishing a database connection" message.

Yes, I HAVE READ Moving WordPress Guide and done everything according to codex. But still, my WP site is down due to Database error.
Please, help me guys!

My website is http://playsterr.com
My inportant WP-Config.php lines:
define('DB_NAME', 'MYDATABASENAME');
define('DB_HOST', '127.0.0.1');
define('WP_SITEURL', 'http://' . $_SERVER['SERVER_NAME'] . '/');

IMPORTANT:
I have migrated from a shared hosting to a cloud hosting. So my team was installed ftp, phpmyadmin, etc manually. Maybe it matters for some settings, I don't know.
Also, one moment. I have SUPER CHACHE PLUGIN Installed. And this thing creates define line and database tables too. Don't know if it matters.

Please guide me what to do in order to make my site live.

Thank you in advance.