I'm just going to post a few findings here about using API scripts to create 300+ emails for a migration from a non-supported control panel - just in case someone else isn't sure what they were doing like me CentOS 8 Stream server, fresh install, only 1 client/site/domain set up, still in testing phase. I customized the ispc-import-csv-email.php script to be able to create both forwarders and mailboxes within the same script. i added a couple extra columns (type, forward_to) to the CSV data, then duplicated the "creation" portion of the script to do either mail_forward_add or mail_user_add based on the type (record['type']). but my biggest issue was getting the script to access the remote/json.php web portal via :8080 i had defined the remote_URL as "https://192.168.0.102:8080/remote/json.php" but as the certificate for the server is self-signed, PHP was complaining without actually complaining - i was getting the message "Could not get mail_policy_get result". testing the remote_URL with WGET, i got a "certificate is not trusted" error. changing from HTTPS -> HTTP gave a "400 Bad Request" error. i finally had to redefine the remote_URL using an actual domain name that was defined in ISPConfig AND had an SSL certificate installed for that specific domain. setting the remote_URL to "https://server.mydomain.tld:8080/remote/json.php" then worked. now there are other errors, but i think those are CSV formatting issues - at least I'm getting data-related errors now!