Zabbix and AWS SES: RCPT failed: 501

[phs]

I am trying to configure media type email to send via AWS SES, but it fails. Server version is 3.4. Settings are in the screenshot attached. Exact error message is:

 30304:20190210:175806.214 failed to send email: Failed sending data to the peer: RCPT failed: 501

SES is set up correctly, is out of sandbox, domain verified, etc. Sending works perfectly with e.g. Postfix, so I am dumbfounded. Any help is appreciated.

Edit: I think it has just now worked with 465 and SSL/TLS settings. However I would like to be able to use STARTTLS as well.

[phs]

It works with STARTTLS now. Perhaps because I added this new media type to the receiving user, otherwise changing nothing else. Solved I guess.