My message crashed recipient mail clients

I am evaluating eM Client. I like it, in spite of few annoying features.
Unfortunately, a couple of people, report a crash of their mail clients, when they try to open my e-mail. I know that one of them is using Outlook and was able to see the message preview, but not to open it.
Is there any settings I have to set to avoid this behavior?
Thanks a lot in advance,
Francesco cafagna

send us few of the problematic mails saved in .eml format - thank you.
My address is [email protected]