Forum Discussion
Grace_LutheranC
Aug 15, 2024Copper Contributor
Outlook emails to Gmail recipients: Get 421-4.7.28 temporary rate limit failure every other mailing
Hello. I am the volunteer IT director for my church. We send out periodic emails to our congregation with announcements from Microsoft 365 Business (Outlook), in which we have set up an email address...
gregschmidt
Aug 16, 2024Copper Contributor
I've started seeing something similar the past couple of months. Mailing list around 120 individuals, about half are GMail addresses. Has worked fine emailing them for years, just lately it's started doing this. If I split the list in half and send the email twice, it works fine. So it's not a volume issue.
Self-run mail server, hosting email for about 15-20 domains, IP address has not changed in a long time, and I have had SPF, DKIM and DMARC set up on this domain for years. My server's email reputation is consistently good, with extremely minimal bounces and complaints relative to the volume of emails sent (which are all opt-in, and CASL compliant). In short, I run a pretty tight ship.
Super annoying when I send out something time-sensitive and half the list doesn't get it.
Self-run mail server, hosting email for about 15-20 domains, IP address has not changed in a long time, and I have had SPF, DKIM and DMARC set up on this domain for years. My server's email reputation is consistently good, with extremely minimal bounces and complaints relative to the volume of emails sent (which are all opt-in, and CASL compliant). In short, I run a pretty tight ship.
Super annoying when I send out something time-sensitive and half the list doesn't get it.
Samd1925
Sep 04, 2024Copper Contributor
Same issue here, I received this for just 21 bcc'd Gmail recipients! Which I have been doing for years as its to a social club.
Remote server returned '550 5.4.300 Message expired -> 421 4.7.28 Gmail has detected an unusual rate of mail originating from your DKIM;domain [MYDOMAIN.onmicrosoft.com 36]. To protect our users;from spam, mail sent from your domain has been temporarily rate;limited.
- Ben12345Feb 25, 2025Copper Contributor
I'm in the same situation as you and have your exact issue. Did you get any resolution?