ERROR [2] mysql_pconnect(): Connection refused

  Fatal error in line 10 of file /var/www/vhosts/trentino-in.com/httpdocs/backoffice/inc_mysql_lib.php, PHP 5.6.40-55+0~20211023.59+debian10~1.gbp650f36 (Linux)

This is the debug trace

Error: "mysql_pconnect(): Connection refused" (error #2).
[PHP Error 2024/11/21 07:29:38]Backtrace:
[PHP Error 2024/11/21 07:29:38]  0: myErrorHandler (line  in )
[PHP Error 2024/11/21 07:29:38]  1: mysql_pconnect (line 10 in /var/www/vhosts/trentino-in.com/httpdocs/backoffice/inc_mysql_lib.php)
[PHP Error 2024/11/21 07:29:38]  2: db_connect (line 61 in /var/www/vhosts/trentino-in.com/httpdocs/backoffice/inc_conn.php)
[PHP Error 2024/11/21 07:29:38]  3: include_once (line 1 in /var/www/vhosts/trentino-in.com/httpdocs/rewrite.php)
[PHP Error 2024/11/21 07:29:38]Variables in myErrorHandler ():
[PHP Error 2024/11/21 07:29:38]Client IP: 18.226.222.76
Aborting...