Apparently some antispam program doesn't like how fastmail sends email? I don't know much about it so I thought I'd ask here. I got this message when trying to send.
The mail system
<address@imtryingtosendto.com>: host filter10.antispamcloud.com[188.138.56.27] said:
550 Sender (mydomainname.com) has no A, AAAA, or MX DNS records. (in reply to
RCPT TO command)
why does this happen? its the only time i've ran into it.