WORKAROUND: Using a local SMTP server that does not require STARTTLS/SSL authentication to send email is one option. It may be possible to configure a SMTP Relay such as this example:
STATUS: There in an Enhancement Request #480679 to review the possibility of adding support for STARTTLS/SSL authentication for Defender Email OTP in a future release of the product. This is not a confirmed Enhancement and there is currently no ETA for this. The Product Manager will periodically review Enhancement Requests for possible inclusion in a future release of the product.