Forum: Bug Report and Feature Requests

But - he received the email notifying him of a reply from one of the recipients of one of the missing messages, so at least some are getting through.

Thanks, but that is not it.
-- I have all screening on my email server turned off. (It's my own domain, not something like gmail.)
-- I have a few filters on my email client, but none of them activated yesterday, when two of the SOL messages were lost. And none of them WOULD activate (when operating properly) on mail from SOL.
-- Checked my Trash folder, and nothing from SOL there. (I trim it once a month down to the past week.)
-- As madnige points out, I am getting emails when an author replies to me, but not for the messages I send to them.
-- I went into settings, and the active radio-button is "Email me copies of received and sent messages".

So I don't think the problem is at my email-receiving components.

BTW, I DO understand the problem you cite with Microsoft. I wrote an app on my web site that allows users to download some programs I have made available. email from that app in respose to user requests gets blocked by gmail (don't know about Microsoft, but Google doesn't like it).

our mail server is completely blocked by Microsoft

Despite Mandrill / mailchimp, the PHPMailer IP 104.200.28.204 is seen as the origin and it is blacklisted as inside a range of poor reputation.

UCEPROTECTL2/L3, you have an IP address from your ISP that falls into a poor reputation range.

So there is nothing you can do if you do not change IP or mask it by sending using the Mandrill API instead of the SMTP interface via PHPMailer.

That's not a guarantee that mandrill isn't also blacklisted...
But you can test it by using Mandrill web interface to send a mail in the name of SOL.