On 9/5/23 16:52, Ben Mustill-Rose wrote:
we were seeing a 5 to 7% block rate on our messages (look at blocks under the statistics section of the dashboard) with Microsoft-owned addresses being the main offenders. We had a feeling that the real number was actually higher based on feedback we received, but ultimately weren't really able to pin down the issue - E.G. was it a non-technical person not knowing they had received the message etc.
With my server (hosted on Linode), it isn't clear whether there are systematic delivery problems at all. Non-responses can have multiple explanations. I know my messages were misclassified as spam by at least one organization hosted by Microsoft 365, but I've sent mail to various other Microsoft 365-hosted addresses without issue. In the confirmed recent case of a false positive, apparently mail from other sources was sometimes misclassified also; hence it wasn't specific to my server. In addition, my server receives a 100% score from the testing tool at internet.nl, suggesting that SPF, DKIM, DMARC, DNSSec and DANE are all configured properly.