Warning: mysqli_real_connect(): (HY000/2002)....

I am getting this e-mail from my site. I got it as soon as I opened the Sales Reports page.
I have not modified any codes or touched any part of the code.

LiteCart 2.5.1

[22-Dec-2022 19:39:17 UTC] Warning: mysqli_real_connect(): (HY000/2002): No such file or directory in ~/includes/library/lib_database.inc.php (Line 26)
← ~/includes/library/lib_database.inc.php (Line 162) in connect()
← ~/includes/library/libsettings.inc.php on line 11 in query()
← ~/includes/autoloader.inc.php (Line 107) in init()
← ~/index.php (Line 19) in {closure}()
Request: GET /ajax/cart.json?=1671722615825 HTTP/2.0
Host: **.com
Client: 85.217.[b]*.*[/b](85.217.[b].[/b])
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36
Referer: https://****.com/admin/?app=reports&doc=monthly_sales

[22-Dec-2022 19:39:17 UTC] Fatal error: Could not connect to database: 2002 - No such file or directory in ~/includes/library/lib_database.inc.php (Line 27)
← ~/includes/library/lib_database.inc.php (Line 162) in connect()
← ~/includes/library/libsettings.inc.php on line 11 in query()
← ~/includes/autoloader.inc.php (Line 107) in init()
← ~/index.php (Line 19) in {closure}()
Request: GET /ajax/cart.json?=1671722615825 HTTP/2.0
Host: **.com
Client: 85.217.*.* (85.217..)
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36
Referer: https://**.com/admin/?app=reports&doc=monthly_sales

Your database server had a temporary cough or you provided the wrong server hostname.
The difference is one is temporary - the other is permanent.
https://stackoverflow.com/questions/1676688/mysql-connection-not-working-2002-no-such-file-or-directory