Error After Upgrading to PHP 8.2

Hi,

After upgrading to PHP 8.2, we are intermittently getting this error,

WARNING: mysqli_real_connect(): (HY000/2002): Connection refused
ERROR: Exception caught in Error: mysqli object is not fully initialized
ERROR: Uncaught Error: mysqli object is not fully initialized in /html/wp-includes/class-wpdb.php:2122 Stack trace: #0 /html/wp-includes/class-wpdb.php(2122): mysqli_ping() #1 /html/wp-content/plugins/backwpup/inc/class-job.php(1014): wpdb->check_connection() #2 /html/wp-content/plugins/backwpup/inc/class-job.php(924): BackWPup_Job->update_working_data() #3 /html/wp-content/plugins/backwpup/inc/class-job.php(2690): BackWPup_Job->log() #4 [internal function]: BackWPup_Job->exception_handler() #5 {main} thrown

And, this warning also,

DEPRECATED: Use of "self" in callables is deprecated

Appreciate the help here.

Cheers,