The site does not see the database (mysql 5.6, openserver)?

Question

PHP

Good day!
Faced the following problem:
I'm running a site with products, a shopping cart, sending letters to the user and administrator and the admin panel.
I must say right away that everything works on the local server, I open the world, it stops working, an error occurs:
Warning: mysqli_connect(): (HY000/2002)

Answer 1

What are the user rights in mysql on the server?
"I open the world" - is it on the same server that you open access from the outside, or roll the site to another server?