We're experiencing a weird issue with outgoing email from our D365 instance, and I'm wondering if anyone can shed any light on the problem.
We're using a hybrid setup, with Dynamics 365 connecting to Exchange on-premise. Ever since this was implemented, we've noted that email sent to any external address is arriving in plain-text, with any rich content/html completely stripped out. This occurs whether we use the Dynamics email composer, onboard email templates or a 3rd party add-in called DocumentsCore Pack to generate the email content.
Email sent to an internal exchange account arrives with formatting intact.
So far, I've had our internal Sys admins look at the issue from the Exchange end, and also engaged with Microsoft support (case still ongoing) but no-one has been able to shed any light on the problem. Has anyone else encountered this issue, and what was your solution?