Upgrading MariaDB 5 to 10

ZC v1.5.8a
php 7.4
phpMyAdmin v4.9.7
MariaDB v5.5.68 / v10.3.29

After upgrading ZC from 1.3.9h to v1.5.8a, everything works fine, and the next thing to do is switch from MariaDB v5 to v10.

I use phpMyAdmin to export the database from MariaDB v5, and import to v10. No error message here, and DB name, username, password are all the same.
Stop v5 and run v10. The website says "There seems to be a problem connecting to our database." Error log shows:

Request URI: /index.php?main_page=product_reviews_info&products_id=2&reviews_id=10&zenid=1k4o01rd1saah9js23cvlhnj30, IP address: 124.243.150.207, Language id
#1 mysqli_connect() called at [/web/includes/classes/db/mysql/query_factory.php:76]
#2 queryFactory->connect() called at [/web/includes/init_includes/init_database.php:22]
#3 require(/web/includes/init_includes/init_database.php) called at [/volume1/web/kendo158/includes/application_top.php:199]
#4 require(/web/includes/application_top.php) called at [/volume1/web/kendo158/index.php:25]
--> PHP Warning: mysqli_connect(): (HY000/2002): No such file or directory in /web/includes/classes/db/mysql/query_factory.php on line 76.

Stop v10 and run v5, and everything is back to normal. It looks like phpMyAdmin can see MariaDB v10 on my server, but ZC can't. Do I miss any step?

siliconbug:

mysqli_connect(): (HY000/2002): No such file or directory

That message typically means that the database is not responding to PHP's connection attempt when using the credentials specified in your /includes/configure.php file, namely:
DB_SERVER
DB_SERVER_USERNAME
DB_SERVER_PASSWORD
DB_DATABASE
DB_PREFIX

All configuration looks correct, and to stop/restart Apache/php/MariaDB 10 doesn't make any difference (in a Linux server).
Finally, I reboot the whole server..., and it works.

Come on, you're a Linux, not Windows!