[zimbra@mail ~]$ cat /opt/zimbra/cyrus-sasl/etc/saslauthd.conf
zimbra_url:
https://mail.ixxxb.net/service/soap/
zimbra_cert_file: /opt/zimbra/conf/smtpd.crt
zimbra_cert_check: off
I've changed it to http://
Now it works! I'll test more, but all looks good.
Thanks a million!