You might find that some emails repeat, e.g. domain deletions emails. Here is how you troubleshoot:
user@server:~$ /usr/bin/php8.1 -q /home/user/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php --poll
Processing Domain Deletions:
----------------------------
Domain : example.com - No Outstanding Invoice
[WHMCS Application] ERROR: PDOException: SQLSTATE[HY000]: General error: 1364 Field 'ipaddr' doesn't have a default value in /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php:308 Stack trace: #0 /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(308): PDO->query() #1 /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(351): domainsync_logActivity() #2 /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(378): domainsync_delDomain() #3 /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(807): domainsync_processDelPoll() #4 /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(1033): domainsync_poll() #5 {main} {"exception":"[object] (PDOException(code: HY000): SQLSTATE[HY000]: General error: 1364 Field 'ipaddr' doesn't have a default value at /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php:308)"} []
PDOException: SQLSTATE[HY000]: General error: 1364 Field 'ipaddr' doesn't have a default value in /home/my/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php:308
#0 /home/user/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(308): PDO->query()
#1 /home/user/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(351): domainsync_logActivity()
#2 /home/user/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(378): domainsync_delDomain()
#3 /home/user/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(807): domainsync_processDelPoll()
#4 /home/user/public_html/modules/registrars/domainsDotCOZA/tools/domains_sync.php(1033): domainsync_poll()
This error is due to MySQL strict mode. See here:
https://docs.whmcs.com/system/database-and-storage/database-and-storage-tutorials/disable-mysql-strict-mode/
mc -e /etc/my.cnf
sql_mode=