Hi!
We run a SaaS customer communication tool called Flixcheck. When sending mails to our customers, we are using an email service provider (CM.com).
Some of our customers (namely those who use Microsoft 365 / Exchange), do not get our emails.
We already investigated this issue with our email service provider, but according to their logs, all emails are perfectly accepted by the M365 servers and not bounced.
Still, our customers say that the emails don't shop up in their inboxes and also do not show up in their junk boxes. Obviously, our emails are silently dropped by M365.
How do we find out, why our mails are dropped and how to stop it? Our customers say that they already whitelisted us as sender, so they can't help here either.
Best regards
Michael
