I did a lookup on the 550 error text and found this snippet: "If you're receiving this error, it means your email message was sent from a server or domain that is currently listed as a high volume spam source by a reputable global black list." ... which is weird because you're not on any blacklists I can see. I did an MX lookup on your domain smallbatchbooks.com and it says there's no DMARC record published, which shouldn't be a good enough reason to block you. This report says your name servers have different MX records, which could be the problem. * https://viewdns.info/dnsreport/?domain=smallbatchbooks.com Mik --- Mik Muller, president Montague WebWorks 239-R Main Street, Greenfield, MA 413-320-5336 http://MontagueWebWorks.com Powered by ROCKETFUSION On 5/27/2020 11:16 AM, Fred Levine via Hidden-discuss wrote: > > I’m wondering if anyone can shed light on this error message (Outlook > for Mac): > > host mx2.hc3579-74.iphmx.com [139.138.58.193] > > SMTP error from remote mail server after DATA: > > 550 #5.7.1 Your access to submit messages to this e-mail system > has been rejected > > I’ve sent multiple messages to the same address with no problem. > Suddenly they’re being rejected. > > Thanks, > > Fred > > Fred Levine > > Small Batch Books > > 493 S. Pleasant St. > > Amherst, MA 01002 > > 413.230.3943 > > > _______________________________________________ > Hidden-discuss mailing list - home page: http://www.hidden-tech.net > Hidden-discuss at lists.hidden-tech.net > > You are receiving this because you are on the Hidden-Tech Discussion list. > If you would like to change your list preferences, Go to the Members > page on the Hidden Tech Web site. > http://www.hidden-tech.net/members -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.hidden-tech.net/pipermail/hidden-discuss/attachments/20200527/5612c1b2/attachment.html>