My wife and are setting up rules to forward messages from certain addresses to each other. We are both using EMClient 9.0.1708. I can set up rules forwarding to her email (email@example.com) OK, but for both of us, EMClient will not accept my email (firstname.lastname@example.org) as a forwarding address (though it is perfectly valid).
Note it will not accept “email@example.com” either. That may not be a real address, but it is perfectly valid syntax.