Hi, using Exchange 365 and GMAIL is bouncing all emails -- unsolicited email from your IP address

Having the same problem here to. We send mail from a gmail address, to a distribution address on exchange. All gmail targets in that distribution list most often end up deferred as rate limited unsolicited mail. Our DKIM, SPF, DMARC all check out. Once the mail arrives in the gmail inbox (sometimes it does after several hours). Looking at the mail headers, there is NOTHING in the mail headers, nor in gmail analysis of it that warnings that anything is weird with it.

This very much smells like a gmail issue.

I have this issue with sending to multiple gmail addresses from my microsoft hosted domain. My DMARC, DKIM and SPF pass the tests at dmarcly.com and mx****. I can send to a few but when I send to large numbers it fails. I do not know what the threshold count of addresses is where it starts to fail.

Remote server returned '550 5.4.300 Message expired -> 421 4.7.28 Gmail has detected an unusual rate of mail originating from your SPF;domain [mydomain.com 35]. To protect our users from spam, mail;sent from your domain has been temporarily rate limited. For more;information, go to; https://support.google.com/mail/?p=UnsolicitedRateLimitError to;review our Bulk Email Senders Guidelines. d75a77b69052e-459aad0bb1esi47654721cf.279 - gsmtp'

Hi,

You said your dkim, dmarc and spf records passes the tests, but did you enabled DKIM in your O365 Admin Center ?

yes though the location of it seems to have moved in the menus unless I am missing something.

The setting for DKIM now seem to be managed here:

https://security.microsoft.com/dkimv2

and there it says authoritative, valid and enabled.

From last few weeks emails with Outlook.in domain have problem but now even Outlook.com also got the similar issue and today it got bounced back.